Denis Peters and Linda McSweeny, Canberra – Australian unions and a prominent law firm have warned that workers rebuilding East Timor could be exposed to asbestos contamination.

Australia has long since cracked down on the handling of asbestos, which can lead to fatal disease later in life for workers, but there were warnings that much of the now banned material exists in East Timor.

The Australian Council of Trade Unions (ACTU) said the United Nations was failing to protect workers involved in reconstruction work from potential asbestos contamination.

Local and international aid and corporate workers and peacekeepers might already have been exposed to asbestos and other harmful substances, ACTU president Sharan Burrow said.

"We are totally supportive of the UN's role in the reconstruction of East Timor," she said in a statement. "But we are concerned that there may have been exposed workers involved in clean-up and construction operations to an unacceptably high risk of exposure to hazardous materials, including asbestos.

"This is an issue not only for local East Timorese workers but also the many Australians in East Timor working for aid agencies, serving as peacekeepers or working for companies who hold reconstruction contracts."

Law firm Slater and Gordon, which has conducted most asbestos litigation in Australia, warned Australian manufacturers of asbestos to act immediately to clean up the situation or face future liability.

It also warned that the UN interim administration in East Timor faced liability for the welfare of Australian and indigenous workers in the clean-up and reconstruction after last year's post-independence vote violence.

The ACTU said it had overwhelming evidence that much of the clean-up operations around Dili after last year's mayhem involved removing and disposing of debris that contained the toxic substance.

Asbestos in East Timor was likely to have come from Australian companies, Slater and Gordon's Ken Fowlie said. "Australian manufacturers responsible for any asbestos debris in Timor have a duty to assist in its safe removal," he said. "The asbestos now being uncovered in Timor, like that in Australia, was sold at a time when authorities knew of the health risks from this deadly product. "We face a new wave of asbestos exposure for those helping with humanitarian and reconstruction work in Timor. "

Mr Fowlie said corporate Australia and the UN was taking on a potential liability unless they did all in their power to protect Australian and indigenous relief workers.

Asbestos Diseases Society of Australia president Robert Vojakovic warned the toll from asbestos in Australia was still rising. "The authorities responsible for work in Timor must remember there is no safe level of asbestos exposure," he said.