AUSTRALIA has been a long-term supplier of uranium to Tokyo Electricity Power Company, operator of the stricken nuclear reactors at Fukushima.

The relationship dates back more than 20 years, when BHP's Olympic Dam mine in South Australia secured the first of several 10-year supply contracts.

A spokeswoman for Resources Minister Martin Ferguson confirmed TEPCO sourced uranium from around the world, including Australia.

The World Nuclear Association reported that exports to Japan accounted for nearly 2500 tonnes of Australia's total exports of 10,700 tonnes of uranium ore in 2008.

Despite that, Australia's uranium miners remain publicly coy about whether they supplied TEPCO.

A spokeswoman for BHP Billiton said the company never disclosed details of its contracts.

''We sell uranium to Japan but we do not give details of specific customers,'' she said.

A spokeswoman for Energy Resources Australia, which operates the Northern Territory Ranger mine, said: ''We don't talk about individual customers for all sorts of reasons, including commercial-in-confidence and security reasons.''

Heathgate Resources said its Beverley uranium mine generally sold to intermediary trading companies, not to end users such as power generators.

Australian Conservation Foundation campaigner David Noonan said TEPCO was on the public record as a buyer of Australian uranium.

''It is either from BHP or ERA or from both. They should acknowledge and assure the Australian community as to what their involvement with TEPCO is,'' Mr Noonan said.

''If TEPCO buy and burn Australian uranium, then it does make us potentially responsible for the current difficulties.''

The Australian Uranium Association's executive director, Michael Angwin, said whether TEPCO was a customer for Australian uranium was beside the point. He said the Australian industry led the development of an international program ''to ensure safe management of uranium through the nuclear fuel cycle''.