Trump promises 'huge tax cut' for Xmas

President Donald Trump has promised a tax overhaul by Christmas, a day after the White House signalled its willingness to strike a healthcare provision from Senate tax legislation if it's an impediment to passing the tax bill.

Speaking before a cabinet meeting on Monday, Trump said: "We're going to give the American people a huge tax cut for Christmas - hopefully that will be a great big, beautiful Christmas present."

At issue is a provision that would repeal a requirement that Americans have health insurance or pay a fine. The provision is not in the version of the tax overhaul passed last week by the House. It is in the bill the Senate Finance Committee has approved.

Repealing a central mandate of the Obama health law has emerged as a major sticking point for Republican senator Susan Collins, whose vote the White House needs. Collins said on Sunday that the issue should be dealt with separately.

Striking the healthcare provision would blow a big hole in the senators' tax cut plan, leaving them $US338 billion short of their revenue goal over the next 10 years.

Senators would have to find the money elsewhere to meet the revenue goal mandated by the budget resolution passed by the Senate and House earlier this year. But so far, there is no consensus among senators on how to come up with the money.

"I don't think anybody doubts where the White House is on repealing and replacing Obamacare. We absolutely want to do it," Mulvaney said Sunday. "If we can repeal part of Obamacare as part of a tax bill and have a tax bill that is still a good tax bill that can pass, that's great.

"If it becomes an impediment to getting the best tax bill we can, then we're OK with taking it out," Mulvaney added.