India got the NSG waiver by consensus, diplomats at the Vienna said on Saturday.

Two days of marathon talks remained inconclusive and fresh discussions have been scheduled later on Saturday.

Five rounds of deliberations on Friday saw diplomats and officials burn the midnight oil to hammer out a consensus that is needed to take the Indo-US nuclear deal forward after facing last minute hurdles.

"We are pleased with the significant progress made throughout the day. India released a very significant statement with regard to its non-proliferation commitments.

"That statement made substantive positive impact on the governments of the NSG that sincerely facilitated the progress that we achieved today," US Acting Under Secretary for Arms Control Affairs John Rood told reporters.

He said the US remained committed to reaching a consensus at the 45-member NSG to allow for the trade in civilian nuclear area.

"It is an important matter, a serious subject that has been given a very serious discussion by our colleagues. I remain optimistic that we can achieve our objective," he added.

Western diplomats, who did not want to be identified, said the negotiations, which were scheduled only for two days, remained inconclusive in the wee hours and would resume later in the day.

The US battled hard overnight to clinch the India-specific waiver from the NSG with diplomats moving back and forth poring over a revised draft. China appeared to have raised concerns that put roadblocks in the way of a consensus.

Suspense mounted over the fate of the revised draft, which was under discussion at the nuclear club with Indian and US officials going over the changes sceptic countries like Austria and New Zealand insisted on incorporating.

As parleys spilled past midnight on changes to woo countries like Austria, Ireland and New Zealand, the US and Indian officials worked on amendments to the draft.

The NSG takes decisions by consensus and a holdout by a few countries can jeopardise an immediate waiver for India.

Austria, which was among a couple of countries holding out, gave enough indications that "more work still" needs to be done that will enable India cross a major hurdle in operationalising the Indo-US nuclear deal.

"Some work still needs to be done. A number of mirror images need to be added to the current talks and ideas in the draft, we want to have more effective and qualitatively improved security architecture," said Peter Launsky, an Austrian Foreign Ministry official.

Launsky said some "auxilliary measures" required to be incorporated in the crucial document. External Affairs Minister Pranab Mukherjee said late on Friday night in New Delhi that "efforts are continuing to evolve a consensus in the NSG."