The Australian National Archives has released ten thousand previously secret cabinet documents from the years 1986 and 1987.

The papers revealed a variety of matters, including the Australian government's concerns over tensions in the relationship between Papua New Guinea and Indonesia.

Now Emeritus Professor in Strategic Studies at the Australian National University, back in the late 1980s Paul Dibb was the Director of the Defence Intelligence Organisation.

He provided advice to the cabinet and warned Australia could lose its entire army – some 30,000 soldiers – if it was required to support PNG in a military conflict along the border with Indonesia.

Presenter: Catherine Graue.

Speaker: Paul Dibb, professor of strategic studies at the Australian National Univeristy.

Dibb: The late 1980s were a time of considerable concern about where the Papua New Guinea-Indonesian border was going. There had been 10 or 12,000 refugees fleeing from what was then called Irian Jaya across the border into refugee camps that were large and causing problems for Papua New Guinea to sustain them. The issue had also been warmimg up over many years. I mean the so called Free Papua Movement which was based along the border on the Papua New Guinea side of the Irian Jaya-Papua New Guinea border had been active on and off since the early 1970s. And that was my clear remembrance as head of the National Assessment staff in the late 1970s. It came to a bit of crisis in 79 when there was only about eight people cleared in Canberra to understand that we had some fairly firm information coming from a covert source in Jakarta that the Indonesian military under General Benny Murdani were getting fed up with this movement of the OPM, the Free Papua Movement, using the protection of being on the Papua New Guinea side of the border and then crossing and then occasionally killing and attacking Indonesian troops. And we took that in the late 70s very seriously. So through the 70s, right through to the late 80s, there were these issues and they were essentially to do with the border, the activities of the OPM, and seen from the perspective of the Indonesian side a situation where they found that this was starting to become intolerable. The 1987 White Paper, which you are aware of, the cabinet documents relating that in my recollection have attached to them the so called Dibb Report which I wrote for the then defence minister, Kim Beasley, about the defence of Australia. There was a classified version of that report which dealt with certain credible contingencies, and there was a highly-classified annexe to that report that was never made public in which I warned the Australian government that if we ever faced a major Indonesian military attack across the border with Papua New Guinea we would have to make our minds up on the contingency of the day. But, and this is the essential point, my advice to the then defence minister Beasley was we could lose the entire Australian army of some 30,000 at the time in the top one tenth of the border between Vanimo and Green River. And we would have no chance of holding that militarily and that would then leave the Australian government of the day with one serious alternative; and that would be to escalate it to strikes of a more serious nature against Indonesian logistics and military centres.

Graue: And how was that advice of yours received?

Dibb: I never go one response to it (laughter)..

Graue: So, in your opinion, how concerned was the Australian government really that relations between Indonesia and Papua New Guinea could deteriorate so much so that it would be forced to step in, and be drawn into a conflict like you've just described?

Dibb: Look, we shouldn't exaggerate it. As you've read from the cabinet documents and I had a hand – by this stage I was deputy secretary of defence for strategic policy and intelligence – in drafting some of that advice and that was our reaction would depend on the situation at the time. In other words, we would not be in the business of encouraging Papua New Guinea to do and pursue provocative acts that could end up in armed conflict. Not only between Indonesia and Papua New Guinea, but clearly given Australia's commitment to Papua New Guinea and its historical and colonial connections, the likelihood we would have to do something about it. With all the dangers that I have mentioned about the length of that border, which from memory is something like 700 kilometres long, and extremely difficult country and whether we would want to escalate into full scale conflict with Indonesia.

It is true that at the time, I became aware many years later when General Murdani had been sacked a minister of defence by the Indonesian Suharto government of the time, and I'm talking here early to mid, more like early 1990s, in a private conversation with me in Australia, he acknowledged that there were serious contingencies in the late 70s along the lines I mentioned of once and for all going across the border in military strength on the Indonesian side and making a sanitised zone if you like. He looked at me with as smile on his face and said, he raised with the 'old man' – meaning president Suharto – and Suharto said to General Murdani, then minister for defence in Indonesia, we are too busy in East Timor.

Graue: There was concern I understand, revealed in these documents, about the ability of the PNG government to handle the situation, and perhaps if it was mishandled by either side, but particularly by the Papua New Guinean government that could have really led to serious issues.

Dibb: Yes. There were serious concerns, as you say. It was not a huge length of time after independence. We had agreed with Papua New Guinea about some principles of helping them in certain military contingencies. And that by the way extended to if we were invited, and let me stress that, if we were invited, to contingencies in which the Papua New Guinea Defence Force mutinied.

And indeed, one such contingency occurred in the late 1980s in which Rabbie Namaliu who was then prime minister rang Bob Hawke, our prime minister at the time, in some agitation that there was an open riot occurring between the Papua New Guinea Defence Force and the Papua New Guinea police in a drunken party they had one Saturday night and that the defence force was breaking into the armoury and getting hold of the weapons. We had a meeting of the augmented chiefs of staff committee at the time, which I attended as deputy secretary, and we looked seriously at what we might do if that situation got out of hand and escalated and the Papua New Guinean government was not able to control its own military. In the end, it petered out and we had to do nothing. But as you know it was a continuing running sore and you've seen in more recent years, and that is the dependability of the Papua New Guinea Defence Force as a disciplined armed force subject to democratic direction and governance.