Jill Jolliffe, Dili – The news that Japan has authorised its troops to serve overseas, despite the country's pacifist constitution, sends shudders down the spine of Marta Pereira, an aged East Timorese woman who lives on the outskirts of Dili.

It means that not only can Japanese forces now join the international military effort to hunt down Osama bin Laden, but that all obstacles have been removed to their return to East Timor, 56 years after their wartime occupation of the territory.

"They're cruel! We don't want Japanese soldiers back here!" she exclaims. She is one of around 1000 surviving East Timorese women who were used as sex slaves, or "comfort women", by the Japanese military. They recently united with other South-East Asian women to demand an apology and compensation. Unlike Germany, Japan has refused to pay reparations to its victims.

The upper house of the Japanese parliament on Monday approved a legal package to allow Japanese soldiers to serve abroad in support of the US-led anti-terrorist coalition, although it stipulated they would be non-combatants. The move is seen as also clearing the way for long-discussed postings to East Timor.

The United Nations Administration in East Timor (UNTAET) has for some time argued in favor of Japanese soldiers joining its peacekeeping force, thus reducing the burden on other countries, a position Australia supports. But the East Timorese population does not share this eagerness. For many, Japan still has accounts to settle with East Timor.

The country's leading women's rights group, Fokupers, has said it does not want Japanese soldiers on East Timorese soil until amends have been made to the comfort women. "We see it as an important issue – despite their old age, these women are still suffering," Natalia de Jesus Cesaltino says.

"We struggled 24 years to get Indonesian troops out of here, and now we're being asked to accept Japanese troops. Japanese support should be in another form. It's ugly to have troops here when no apology has yet been made."

Twelve leading East Timorese organisations have signed a petition against the return.

UNTAET is in a dilemma. Japan already gives generous support in another form: it tops the list of cash aid donors to the UNTAET budget, with a current contribution of $US23.9 million ($A47 million). Administrator Sergio Vieira de Mello is anxious to avoid offending East Timor's new benefactors and eager for Japanese soldiers to join the UN military soon. "We will be in trouble unless the [Japanese forces] arrive by November when the rainy season starts," he said recently.

Little was known before 1999 about the fate of East Timorese women during World War II. Since Indonesia's withdrawal from East Timor that year, women have raised their profile and publicised the comfort women issue.

A half-hearted bid had been made by Indonesian lawyer Abdul Hakim to include East Timorese in an Asia-wide reparations claim against Tokyo in the dying days of the Suharto regime, but it came to nothing.

Marta Pereira was one of 25 girls held in a barracks in Bobonaro, near the East Timor border. They were forced to have sex with queues of Japanese soldiers each night. She was a virgin. Her brutal initiation and subsequent suffering marked her forever.

The life of Marta's daughter, Catarina Pereira, 48, has been overshadowed by her mother's experience. Her mother first told the story when she was around 10, too young to really understand it. "She told it with great anger," she says. "What can I do? I can only give her support and attempt to alleviate her sadness."

Marta is a tall, dignified, octogenarian whose anger still devours her. Catarina said she sleeps very little, wandering around the house at night. She hears her speaking to imaginary figures, ghosts from her troubled past.

Last year two Timorese comfort women testified at a mock trial of the Japanese military held in Tokyo. UN legal officers helped them prepare an indictment based on the known facts in Japanese-occupied Timor, but it was decidedly non-official support.

One of the witnesses was Esmeralda Boe, of the border town of Memo. Three years before the war ended she was husking tapioca in her garden when a Japanese commander ordered her to come with him. He told her that her family would be hanged if she did not obey.

She was still physically a child. The pain she suffered from the rape was severe. In the first days she was unable to walk. "I cried a lot," she says, "and I could never sleep."

Esmeralda still remembers a Japanese song, which she sings in a strong, clear voice that soars over the palm groves of her village. She doesn't know what it means, but the memory of her suffering is as vivid as her memory of the words.

Although the UNTAET indictment stated that the women were rounded up on behalf of the Japanese military by local chiefs, this is wrong. The chiefs were acting on orders of the Portuguese governor of the time, Manuel Ferreira de Carvalho. Portugal, then ruled by the dictator Salazar, was officially neutral in a conflict in which both Japanese and Australian soldiers initially occupied East Timor.

A secret report by the governor released in Lisbon some years ago shows that he collaborated with the Japanese in rounding up Timorese women, against the protests of other Portuguese officials. His justification, he said, was to save European women from rape by Japanese soldiers by providing them with indigenous women who were already prostitutes – although there is no evidence the women in question were.

During rule by the Portuguese dictatorship for most of the 20th century, interrupted by Japanese and Indonesian military occupations, East Timorese women have generally been treated as chattels in a brutal colonial universe. Now on the brink of independence, they are seeking to assert a different identity. But considerations of realpolitik by the UN in a rapidly changing world order make it unlikely they will succeed in the short term.