The US Senate has passed legislation to reopen the government, bringing the longest shutdown in history closer to an end as a small group of Democrats ratified a deal with Republicans despite searing criticism from within their party.

The 41-day shutdown could last a few more days as members of the House, which has been on recess since mid-September, return to Washington to vote on the legislation. President Donald Trump has signaled support for the bill, saying on Monday that “we’re going to be opening up our country very quickly.”

The final Senate vote on Monday, 60-40, broke a grueling stalemate that lasted more than six weeks as Democrats demanded that Republicans negotiate with them to extend health care tax credits that expire January 1. The Republicans never did, and five moderate Democrats eventually switched their votes as federal food aid was delayed, airport delays worsened and hundreds of thousands of federal workers continued to go unpaid.

House Speaker Mike Johnson urged lawmakers to start returning to Washington “right now" given shutdown-related travel delays. “We have to do this as quickly as possible," said Johnson, who has kept the House out of session since mid-September, when the House passed a bill to continue government funding.

After weeks of negotiations, a group of three former governors in the Senate – Jeanne Shaheen and Maggie Hassan, both of New Hampshire, and independent Angus King of Maine – agreed to vote to advance three bipartisan annual spending bills and extend the rest of government funding until late January. Republicans promised to hold a vote to extend the health care subsidies by mid-December, but there was no guarantee of success.

Shaheen said on Monday that “this was the option on the table” after Republicans had refused to budge.

“We had reached a point where I think a number of us believed that the shutdown had been very effective in raising the concern about health care," she said, and the promise for a future vote “gives us an opportunity to continue to address that going forward".

The legislation includes a reversal of the mass firings of federal workers by the Trump administration since the shutdown began on October 1. It also protects federal workers against further layoffs through January and guarantees they are paid once the shutdown is over.

In addition to Shaheen, King and Hassan, Democrat Tim Kaine of Virginia, home to tens of thousands of federal workers, also voted in favor of moving forward on the agreement. Dick Durbin of Illinois, the No 2 Democrat, Pennsylvania's John Fetterman and Nevada's Catherine Cortez Masto and Jacky Rosen also voted yes. All other Democrats, including Senate Democratic leader Chuck Schumer of New York, voted against it.

The moderates had expected a larger number of Democrats to vote with them as 10 to 12 Democratic senators had been part of the negotiations. But in the end, only five switched their votes – the exact number that Republicans needed. King, Cortez Masto and Fetterman had already been voting to open the government since October 1.

Schumer, who received blowback from his party in March when he voted to keep the government open, said he could not “in good faith” support it after meeting with his caucus for more than two hours on Sunday.

“We will not give up the fight,” he said, adding that Democrats have now “sounded the alarm” on health care.

Independent Bernie Sanders of Vermont, who caucuses with the Democrats, said giving up the fight was a “horrific mistake.” Chris Murphy of Connecticut agreed, saying that voters who overwhelmingly supported Democrats in last week's elections were urging them to "hold firm”.

House Democrats swiftly criticized the Senate.

Texas Rep. Greg Casar, the chairman of the Congressional Progressive Caucus, said a deal that doesn’t reduce healthcare costs is a “betrayal” of millions of Americans who are counting on Democrats to fight.

Others gave Schumer a nod of support. House Democratic leader Hakeem Jeffries had criticized Schumer in March after his vote to keep the government open. But he praised the Senate Democratic leader on Monday and expressed support for his leadership throughout the shutdown.

“The American people know we are on the right side of this fight,” Jeffries said Monday, pointing to Tuesday's election results. (AP)