CANBERRA - Australia's defence chiefs pushed for atomic weapons research as part of the nation's nuclear energy programme, despite the signing of the non-proliferation treaty 15 months earlier, secret 1971 cabinet documents reveal.

The aim was to reduce the time it would take Australia to build and deploy nuclear bombs if the nation came under serious threat.

The documents, released today by the National Archives of Australia under the 30-year confidentiality rule, reflect Australia's deepening concern at the rise of China, Japan and India, and the military's belief that the nation must retain a nuclear option.

Two years earlier, the cabinet had received detailed costings on a nuclear arsenal, and had conceived plans for a chain of nuclear power stations around Australia.

But no further steps toward atomic weaponry had been taken, and the energy proposal contracted first to a single nuclear plant at Jervis Bay, south of Sydney, and finally to maintaining the sole research reactor at Lucas Heights in Sydney.

That reactor, commissioned in 1958, is at present the centre of furious controversy over plans for a replacement plant.

Australia signed the first nuclear test ban treaty in 1963.

It joined the Nuclear Non-Proliferation Treaty in February 1970.

But a secret report on the strategic future facing Australia in the decade after America's imminent abandonment of South Vietnam and the withdrawal of Britain from Asia shows that powerful forces within Canberra were lobbying hard to keep the nuclear door open.

The report, presented to the cabinet in June 1971, paid heed to the continuing shelter afforded by the United States' nuclear umbrella, but also noted the rise of a nuclear-armed China, the possibility of Japan and India joining the atomic bomb club, and increasing superpower interest in the Indian Ocean and southwest Pacific.

The report said there was no need at the time of writing for Australia to develop or acquire nuclear weapons.

But the implication of China's nuclear capacity, and of the growth of military technology in Japan and India, needed continuous review.

"We consider that the opportunities open to the Australian Government in future would be enlarged if the lead time for the acquisition of a nuclear weapons capability could be shortened," the defence chiefs said.

"We recommend regard to this, without undue claims upon resources, in the future development of Australia's nuclear capacity for peaceful purposes, in the defence research and development programme, and in other relevant ways."

The cabinet accepted the report without giving specific mention to the nuclear research proposal.