WASHINGTON (AFP) – US Vice President Joe Biden has expressed confidence in budget talks aimed at averting a government shutdown, saying lawmakers had agreed to $73 billion in cuts over the next six months.

"I think we're making good progress," Biden told reporters after meeting with Senate Democratic leaders on Capitol Hill.

"There is no reason why, with all what's going on in the world and with the state of the economy, we can't reach an agreement to avoid a government shutdown, because the bottom line here is we?re working off the same number."

The White House's Republican foes had originally sought $100 billion in cuts from President Barack Obama's 2011 budget request, in a bid to fulfill a campaign pledge to reduce spending for federal agencies to pre-Obama levels.

Biden's figure included the $40 billion in cuts his fellow Democrats had originally sought plus an additional $33 billion.

Both Republicans and Democrats stressed, however, that the latest figure being considered is only tentative and could change depending on the outcome of the protracted negotiations.

"There is no deal until everything is settled -- spending cuts and policy restrictions," said Michael Steel, spokesman for House Speaker John Boehner.

Biden echoed the comment, saying: "It's not a deal until it's a whole deal."

Without an agreement on the budget to finance the federal government for the remainder of fiscal year 2011, which ends September 30, the Obama administration's non-essential services will shut down after April 8.

Congress has adopted six temporary stopgap spending bills, known as continuing resolutions, so far this year.

Biden would not confirm which political proposals, known as "riders," the White House might accept as part of a deal.

Republicans have namely sought to block government regulation of greenhouse gases and federal funding to Planned Parenthood, which provides contraception and family planning services in the United States. By law, the group already cannot use any federal funding for abortions.

"There are certain things we're just not going to do on riders, even if you agree with everything else. We're just not going to do it," Biden said.

Democrats have noted that those measures include the proposed limits on greenhouse gas controls.