The United States ambassador to India says Washington is on its way to meeting key deadlines that will finalise a controversial nuclear deal with New Delhi.

David Mulford's comment comes a day after India's prime minister, Manmohan Singh, survived a confidence vote that allows him to move forward with the pact.

Mr Mulford says the legislation for the deal needs to be back with Washington for ratification before the US congress adjourns.

But before this, India must sign a safeguards agreement with the UN's International Atomic Energy Agency to inspect civilian nuclear reactors.

It must also obtain a waiver from the 45-state Nuclear Suppliers Group whose rules ban trade for countries that have not signed the Non-Proliferation Treaty.

Once these steps are accomplished, the US congress will act on the legislation enabling India to acquire nuclear plants and related technology for civilian use.

Produced by Radio Australia and Australia Network