The US Congress is aiming to end a dispute over border security with legislation that would ignore President Donald Trump's request for $US5.7 billion ($A8 billion) to help build a wall on the US-Mexico border but avoid a partial government shutdown.
Late on Wednesday, negotiators put the finishing touches on legislation to fund the Department of Homeland Security (DHS) through September 30, the end of the fiscal year, along with a range of other federal agencies.
Racing against a Friday midnight deadline, when operating funds expire for the agencies that employ about 800,000 workers at the DHS, the departments of Agriculture, Commerce, Justice and others, the Senate and House of Representatives aimed to pass the legislation later on Thursday.
That would give Trump time to review the measure and sign it into law before temporary funding for about one-quarter of the government expires.
Failure to do so would shutter many government programs, from national parks maintenance and air traffic controller training programs to the collection and publication of important data for financial markets, for the second time this year.
"This agreement denies funding for President Trump's border wall and includes several key measures to make our immigration system more humane," House Appropriations Committee Chairwoman Nita Lowey, a Democrat, said in a statement.
According to congressional aides, the final version of legislation would give the Trump administration $US1.37 billion ($A1.92 billion) in new money to help build 88.5 km of new physical barriers on the southwest border, far less than what Trump had been demanding.
It is the same level of funding Congress appropriated for border security measures last year, including barriers but not concrete walls.
Since he ran for office in 2016, Trump has been demanding billions of dollars to build a wall on the southwest border, saying "crisis" conditions required a quick response to stop the flow of illegal drugs and undocumented immigrants, largely from Central America.
He originally said Mexico would pay for a 3200km concrete wall - an idea that Mexico dismissed.
Trump has not yet said whether he would sign the legislation into law if the Democratic-controlled House of Representatives and Republican-led Senate approve it, even as many of his fellow Republicans in Congress were urging him to do so.
Instead, he said on Wednesday he would hold off on a decision until he examines the final version of legislation.
But Trump, widely blamed for a five-week shutdown that ended in January, said he did not want to see federal agencies close again because of fighting over funds for the wall.
