The Federal Government will take a more active role against nuclear weapons, Foreign Minister Stephen Smith said, pledging not to sell uranium to nuclear-armed India.

Last month the Government said it would scrap a landmark deal to sell uranium to India for civilian use because it has not signed the Non-Proliferation Treaty (NPT).

The rejection carries weight as Australia has the world's largest known reserves of uranium with about one-quarter of the world's supply.

"The current Government has a longstanding policy commitment as a political party and from opposition that we will not authorise the export of uranium to a country which is not a party to the nuclear Non-Proliferation Treaty," Mr Smith told a news conference on a visit to Tokyo.

"The nuclear Non-Proliferation Treaty has always been supported by Australia.

"The current Australian Government came to office with a new commitment to seek to be much more active... as a nation on nuclear non-proliferation and disarmament matters."

The deal with India was struck by former prime minister John Howard last August before elections in November last year.

Mr Howard, a close ally of US President George W Bush, argued that the deal with India was subject to strict guarantees that the fuel would be only for non-military use.

The US called on Australia to show the same commitment to sell uranium to India as to China, which has nuclear weapons but has also signed the NPT.