Anthony Hubbard – Greig Cunningham has learned the hard way about governments and foreign affairs. His brother Gary, a television cameraman, was killed during Indonesia's attack on Balibo in East Timor in 1975.

The New Zealand government, says Cunningham, didn't want to know about Gary's death, although he was born and raised in New Zealand and was a New Zealand citizen. It was too busy defending the Indonesians.

"It might seem slightly cynical not believing that governments always tell the truth all the time," Cunningham says from his home in Melbourne. But "one of the most disappointing things which has happened in this whole episode is the way we've been treated by our governments on all sides".

Cunningham is a mild man, not given to exaggeration. When he talks about government cover-ups and official lying, he does not use the words casually. But the Cunningham family has suffered 30 years of grief and double-talk. Indonesia invaded the former Portages colony of East Timor in late 1975 and occupied it for 25 years, during which about 200,000 people, or a third of the population, are estimated to have died.

But in the past 10 years researchers have used freedom of information laws in Britain, America, Australia and New Zealand to piece together the truth about what some have described as a genocide.

The then-US president, Gerald Ford, visited Jakarta hours before the invasion and made it plain to Indonesian president Suharto that the US would not oppose it. US official records show Secretary of State Henry Kissinger told Suharto: "It is important that whatever you do succeeds quickly."

Other Western countries, including Britain, Australia and New Zealand also thought East Timor could not govern itself and should be part of Indonesia. They too told the Indonesians in private that they "understood" the Indonesian position and connived at the invasion.

And New Zealand, says East Timor and Indonesian human rights campaigner Maire Leadbeater, who has just finished the manuscript of a book about the issue, "played a far more significant role in East Timor's tragedy than has ever been acknowledged".

"We did not simply follow a path trodden out by big brother Australia, as is sometimes suggested. New Zealand made its own unique contributions to help Indonesia out on the international stage."

The latest revelations come from London, where newly-revealed documents show the British government proposed to lie about Indonesian atrocities. It also decided not to lobby Indonesia over the death of the journalists, even though two of them were British.

The British Ambassador in Jakarta, John A Ford, said in a secret telegram to London on December 24, 1975 that Indonesian invading forces in East Timor's capital Dili had gone "on a rampage of looting and killing". "If asked to comment on any stories of atrocities," he told the Foreign and Commonwealth Office, "I suggest we say we have no information."

In an earlier message, on October 24, he said the five journalists – two Australians, two Britons and Gary Cunningham, a cameraman for Australia's Channel Seven – had been killed on October 16. "Their bodies were immediately disposed of by the local commander, probably by burning.

"We have suggested to the Australians that since we, in fact, know what happened to the newsmen it is pointless to go on demanding information from the Indonesians which they cannot, or are unwilling to provide... Since no protests will produce the journalists' bodies, I think we should ourselves avoid representations to the Indonesians about them, they were in a war zone of their own choice."

These documents – issued to researcher Hugh Dowson and widely publicised this month in the British media – have many parallels in New Zealand archives.

The documents, issued under the Official Information Act over the years, echo the British and American ones. Like Britain, New Zealand tacitly supported the Indonesian invasion, while publicly talking about the right of the Timorese people to determine their own fate.

Ministry of Foreign Affairs senior staffer Merwyn Norrish told visiting Indonesian officials in Wellington on December 8, 1975 that New Zealand "had a private and a public position with respect to Timor".

In correspondence made public only in 2002, Norrish said: "Publicly we had sought to emphasise the need for an act of self-determination, wherever that might lead, while privately we acknowledged that the most logical solution would be one that led to (Indonesian) integration (of East Timor) through self-determination."

In a cable to New Zealand embassies overseas on November 26, the ministry had referred to the same private position of preferring integration with Indonesia, adding: "the government couldn't state this publicly, however".

The journalists, who had filmed Indonesian troops storming into the border town of Balibo, were a serious obstacle to officials wanting to downplay an Indonesian attack.

One – presumably Australian – source told a New Zealand diplomat in November 1975 that there were "about 5000 invading troops" in Timor. He also spoke about "the difficulties that have arisen in the bilateral relationship with the Indonesians.

"The (assumed) death of the five journalists was the first irritant, and journalists have since tended to be a primary source of difficulty," the New Zealand embassy in Canberra says in a cable to Wellington about the briefing on November 7.

The source complained the journalists associated with Fretilin – the armed Timorese independence movement that resisted the Indonesian invasion – were sympathetic to the Fretilin cause.

For Greig Cunningham, one New Zealand official document sums up the government's attitude towards his brother Gary.

A June 29, 1976 Foreign Affairs paper warned Foreign Minister Brian Talboys that pressing a case against Indonesia over the killing of the journalists "would harm our own relations with Indonesia".

The journalists had died during the attack, and only Fretilin sources claimed all five were executed, the officials said. There seemed no clear-cut case against Indonesia of violation of international law.

If Australia did press the case against Indonesia, "largely in response to domestic political pressure, New Zealand will be faced with a difficult situation because of Mr Cunningham's nationality", the briefing says.

But it noted: "Mr Cunningham, while a New Zealand citizen, was an Australian resident, was employed by an Australian organisation, was a member of the Australian Journalists' Association, and his closest relations live in Australia.

"The Australian Government, if it proceeds, will do so on behalf of all five journalists since they were Australian residents and there would be no need for New Zealand to present a separate case. Accordingly, there would be no necessity for New Zealand to become involved in the dispute."

Cunningham, who with most of his family has lived in Australia since the 1970s, says "this is not nice to read". The New Zealand officials "are basically saying, 'Look, he's lived in Australia, let the Australians handle it.' Well, he had lived in Australia, but it was only for a few years, and he was still a New Zealander."

The New Zealand government was saying, in effect, that it wasn't going to bother about one of its own citizens. And when the alleged remains of the journalists were buried in Jakarta on December 5, no New Zealand official attended the funeral – although British and Australian diplomats did.

This, says Cunningham with characteristic understatement, was "very difficult" for the family. But the latest London documents showed the British were also underplaying the deaths of their citizens, he said. And the family had known for a long time that the Australian government has not been frank.

Maire Leadbeater says: "It's particularly appalling we behaved this way when it was a New Zealand citizen's life in question." But, she says, a later government behaved similarly when New Zealander Kamal Bamadhaj was shot by Indonesian troops during the massacre of independence protesters in Dili in 1991.

The public pressure on the New Zealand government over Bamadhaj was much greater, says Leadbeater. "But they were trying to do exactly the same, trying to close it down as quickly as possible."

Investigations by Australian journalists have uncovered strong evidence that the Indonesian invaders and Timorese helpers executed the journalists in cold blood. Journalist Jill Jolliffe's 2001 book Cover-Up: the Inside Story of the Balibo Five, identifies some of the alleged killers by name.

Former Foreign Affairs Minister Phil Goff regrets New Zealand's lack of support for the Cunninghams. "New Zealand has a responsibility towards its nationals abroad and to assisting their families in circumstances such as this," he told the Sunday Star-Times.

The Timor policy – followed by governments of right and left until 1999, when New Zealand abruptly switched to a Timorese independence line after president Bill Clinton changed the US position – was also wrong, Goff says.

"We are committed to principles of international relationships set out under the United Nations and should have clearly and firmly opposed the invasion and subsequent abuses of human rights." Nor should New Zealand have had a different private policy from its stated one. "Public and private positions should be consistent."

So why did New Zealand take such a tough and two-faced pro-Indonesian line for so many years? Its defenders say the policy must be understood in the context of the Cold War. Washington wanted to show South-East Asia – and especially Indonesia, the anti-communist regional power – that it was a dependable ally despite the US defeat in Vietnam in April 1975.

Indonesia said it was worried an independent East Timor would provide a haven for forces wanting to break up the Indonesian state. Western powers believed the desperately poor former Portuguese colony, cast adrift after a left-wing coup ousted the right-wing dictatorship of Portugal, was not a viable country.

National Party leader – later prime minister – Robert Muldoon told president Suharto in early 1975 "a completely independent Portuguese Timor was not a viable proposition".

The most striking example of this attitude was a report by Roger Peren, New Zealand's ambassador in Jakarta, about his visit to Indonesian-occupied East Timor in January 1978. His distaste is evident.

The East Timorese people, he wrote, "are poor, small, riddled with disease and almost totally illiterate, very simple and, we were told again and again, 'primitive'.

"Considered as human stock they are not at all impressive – and this is something that one has to think about when judging their capacity to take part in an act of self-determination or even to perform as responsible citizens of an independent country".

Leadbeater says she was repelled by this report: it was "a horrible thing, I don't even want to read it really". She points out these "unimpressive" people defied a reign of terror started by pro-Indonesian militiamen during the UN-supervised referendum in 1999 and voted overwhelmingly for independence.

Two years ago, Helen Clark accused New Zealand officials of misleading Labour prime minister Bill Rowling over the issue in 1975 -a charge the officials angrily reject.

Leadbeater, having studied the documents, thinks officials were "doing a Yes Minister, leading and steering the PM". "But... politicians must ultimately take responsibility."

Rowling signed the statement that merely "regretted" the full-scale invasion on December 8. He put his name to the press release, drafted by Foreign Affairs, saying NZ was impressed by the "restraint" shown by the Indonesians during the attacks on East Timor in mid-October.

He even watered down an earlier statement saying New Zealand would be "gravely concerned" if Indonesia intervened. An official told Leadbeater Rowling removed the word "gravely".

New Zealand had alternatives at the time, Leadbeater says. It did not simply have to toe the line of the Indonesian hawks. A report by the New Zealand defence attache in Jakarta on October 8, 1975 said that before the latest attacks "the Indonesian military was divided between hawks and doves – the former, a comparative minority". The doves apparently included Suharto, who "has continued to set his face against direct military intervention", he wrote.

Leadbeater says New Zealand could have aligned itself with the doves and tried to persuade Indonesia against the attack. She believes this could have made the difference at a vital time. Instead, New Zealand backed the invaders – and even played an important role in lobbying at the UN against moves to condemn Indonesia. In other words, "we didn't just turn a blind eye to Indonesia, as is sometimes claimed", says Leadbeater. "We actively supported them."

But retired foreign affairs chief Merv Norrish, who has rarely spoken publicly about the East Timor issue, says the idea that the invasion could have been prevented is "rubbish, utter rubbish. Do you seriously think they (the Indonesians) would have been willing to have that sort of little state with no political experience right on their border? I don't".

Greig Cunningham still wants accountability and justice. Each year the family remembers Gary. "(He is) still part of our lives. He was killed on October 16 and my sister Ann's birthday is the 17th. She was the youngest and he was the oldest and they absolutely adored each other."

His father Jim was "a man's man" and didn't "rail against the world" over Gary's death. "But basically it ate him up so much, to the point in the last few years of Dad's life if anything came up about East Timor he wouldn't talk about it."

He wishes his father had been alive in 2003, when the Cunninghams joined the families of the other journalists at a ceremony in Balibo to commemorate the men. For the first time, the families were able to see the place where their loved ones were killed.

Yet his father would probably have refused to come. "I think it would have been just too hard."

Cunningham says the family does not want vengeance. "None of us agree with the death penalty... But there are a couple of individuals swanning around in East Timor and Indonesia who shouldn't be – they committed crimes, and not just against the journalists, but other war crimes."

Some Western politicians and officials are now prepared to say sorry. In 1999, former Australian Cabinet Minister Doug Everingham, a member of the pro-Indonesian Labour administration of Gough Whitlam, apologised for accepting the invasion.

And in a letter to the Times newspaper in London this month, former British diplomat Andrew Stuart apologised for saying in 1975 that it was "probably inevitable and understandable" Timor should be incorporated in Indonesia.

He wrote, "I overestimated the sense of the Indonesian generals and underestimated the warlike qualities of the Timorese. At the time I, and most other observers, got it wrong and I apologise. What more can a civil servant do?"

Norrish has a different view. He recommended the pro-Indonesian line to the government, and backed its decision to apply it. "That was what was believed at the time in the circumstances of the time to be the sensible course. And I have no apology to make for that at all."