WASHINGTON (AFP, REUTERS) - United States congressional leaders have reached a deal on a federal spending bill which if passed by lawmakers this week will avert a government shutdown, a top lawmaker and congressional aides said late on Sunday (May 1).

The agreement would keep federal operations running through Sept 30, the end of the fiscal year.

Congress is expected to vote in the coming days on the package, which aides said includes some US$1.5 billion (S$2.1 billion) in funding for increased border security measures, but no funding for an actual wall.

They also said it adds US$2 billion in new funding for the National Institutes of Health, and is expected to increase military spending.

Comprehensive details were not available on Sunday as the measure had yet to be officially finalised and released.

The House of Representatives and Senate must approve the deal before the end of Friday and send it to President Donald Trump for his signature to avoid the first government shutdown since 2013.

The House is likely to vote first on the package, probably early in the week and send the measure to the Senate for approval before Friday's midnight deadline when existing funds expire.

If this deal passes Congress and the president signs it into law, as expected, it would mark the first significant bipartisan legislation passing Congress this year and since Trump took office on Jan 20.

Congress averted a US government shutdown last Friday by voting for a stop-gap spending bill that gave lawmakers another week to work out federal spending over the final five months of the fiscal year.

Even with the new progress, lawmakers are running far behind schedule, as legislation funding government operations in fiscal year 2017 were supposed to have been completed by last Oct 1.

"This agreement is a good agreement for the American people, and takes the threat of a government shutdown off the table," Senate Minority Leader Chuck Schumer said in a statement.

"The bill ensures taxpayer dollars aren't used to fund an ineffective border wall, excludes poison pill riders, and increases investments in programs that the middle-class relies on, like medical research, education, and infrastructure."

Trump made building the wall one of the primary pledges of his presidential campaign, insisting it would begin within his first 100 days, a milestone that came and went on Saturday.

Last week White House aides acknowledged the administration could wait until later this year or next year to consider funding for the wall.