US President Donald Trump and his Democratic opponents appeared to make little progress at a White House meeting aimed at heading off a government shutdown that could disrupt a wide range of services as soon as Wednesday.

Both sides emerged from the meeting saying the other would be at fault if Congress fails to extend government funding beyond a Tuesday midnight deadline.

"I think we're headed to a shutdown," Vice President JD Vance said.

Democrats say any agreement to extend that deadline must also preserve expiring health benefits, while Trump's Republicans insist health and government funding must be dealt with as separate issues.

Senate Democratic Leader Chuck Schumer said the two sides "have very large differences."

If Congress does not act, thousands of federal government workers could be furloughed, from Nasa to the national parks, and a wide range of services would be disrupted. Federal courts might have to close and grants for small businesses could be delayed.

Trump is threatening to extend his purge of the federal workforce if Congress allows the government to shut down.

Only a handful of agencies have so far published plans detailing how they would proceed in the event of a shutdown.

At issue is US$1.7 trillion in "discretionary" spending that funds agency operations, which amounts to roughly one-quarter of the government's total US$7 trillion budget.

Much of the remainder goes to health and retirement programs and interest payments on the growing US$37.5 trillion debt.

Prior to the White House meeting, Democrats floated a plan that would extend current funding for seven to 10 days, according to Democratic sources, which could buy time to hammer out a more permanent agreement.

That is shorter than the timeline backed by Republicans, which would extend funding to November 21.

After returning to the Capitol, Schumer told reporters he would not accept a shorter funding bill.

Senate Republican Leader John Thune sought to pile pressure on Democrats by scheduling a Tuesday vote on the Republican bill, which has already failed once in the Senate.

Healthcare is a key issue. Roughly 24 million Americans who get coverage through the Affordable Care Act will see their costs rise if Congress does not extend temporary tax breaks due to expire at the end of this year.

House Democratic Leader Hakeem Jeffries said Congress needs to make those tax breaks permanent now because higher health insurance premiums are being finalized and the new signup period starts November 1.

"We believe that simply accepting the Republican plan to continue to assault and gut healthcare is unacceptable," Jeffries said at a Monday press conference.

Republicans say they are willing to consider the issue, but not as part of a temporary spending patch.

"They had some ideas that I actually thought were reasonable, and they had some ideas that the president thought was reasonable. What's not reasonable is to hold those ideas as leverage and to shut down the government," Vance said. (Reuters)