Donald Trump may have backed down on his Mexico wall plan.

President Donald Trump has stepped back from demanding a down payment for his border wall in must-past spending legislation, potentially removing a major obstacle to a bipartisan deal just days ahead of a government shutdown deadline.

Trump told a gathering of around 20 conservative media reporters on Monday evening that he would be willing to return to the wall funding issue in September, according to two people who were in the room who spoke on condition of anonymity.

The border wall money is fiercely opposed by Democrats, whose votes are needed to pass the government-wide spending legislation that comes due on Friday at midnight.

The wall is also unpopular with many Republicans, and GOP negotiators on Capitol Hill were uneasy about the clash over the wall potentially sparking a government shutdown.

Senate Minority Leader Chuck Schumer of New York, who has a key role providing Democratic votes to pass the legislation, welcomed Trump’s reported shift on the wall.

“It’s good for the country that President Trump is taking the wall off the table in these negotiations,” Schumer said.

“Now the bipartisan and bicameral negotiators can continue working on the outstanding issues.”

The wall was the most pressing issue confronting lawmakers as they returned from a two-week spring recess to face a critical deadline.

Congress must pass a $US1 trillion ($A1.3 trillion) catch-all spending bill to pay for all agencies of government or trigger a partial shutdown on Saturday, which happens to coincide with the 100th day of Trump’s presidency.

The negotiations over the spending bill took centre stage despite a separate White House push for fast action to revive health care legislation to repeal and replace the Affordable Care Act.

After signalling last week that they hoped for a vote as soon as this week on a rewritten health bill, White House officials softened their stance.

Echoing the views of House GOP leaders, White House press secretary Sean Spicer said there would be a vote on health care legislation when House leaders count the 216 votes needed to pass it.

With Democrats unanimously opposed, it remains to be seen whether the health care deal will come together and attract the needed support.

Trump also pushed for his border wall, a central campaign pledge that he still insists Mexico will pay for in the end, though Democrats and even most Republicans doubt that will ever come to pass.