US Senate Republicans passed President Donald Trump's massive tax-and-spending bill on Tuesday by the narrowest of margins, advancing a package that would slash taxes, reduce social safety net programs and boost military and immigration enforcement spending while adding US$3.3 trillion to the national debt.

The House of Representatives will now consider giving the legislation final approval.

A handful of Republicans there have already voiced opposition to some of the Senate provisions.

Trump wants to sign it into law by the July 4 Independence Day holiday, and House Speaker Mike Johnson said in a statement that he aimed to meet that deadline.

The measure would extend Trump's 2017 tax cuts, give new tax breaks for income from tips and overtime pay and increase spending on the military and immigration enforcement.

It also would cut about US$930 billion of spending on the Medicaid health program and food aid for low-income Americans and repeal many of Democratic President Joe Biden's green-energy incentives.

The legislation, which has exposed Republican divides over the nation's fast-growing US$36.2 trillion debt, would raise the federal government's self-imposed debt ceiling by US$5 billion. Congress must raise the cap in the coming months or risk a devastating default.

The Senate passed the measure in a 51-50 vote with Vice President JD Vance breaking a tie after three Republicans – Thom Tillis of North Carolina, Susan Collins of Maine and Rand Paul of Kentucky – joined all 47 Democrats in voting against the bill.

The vote followed an all-night debate in which Republicans grappled with the bill's price tag and its impact on the US healthcare system.

Much of the late horse-trading was aimed at winning over Republican Senator Lisa Murkowski of Alaska, who had signaled she would vote against the bill without significant alterations.

The final Senate bill included two provisions that helped secure her vote: one that sends more food-aid funding to Alaska and several other states, and another providing US$50 billion to help rural hospitals cope with the sweeping cuts to Medicaid.

The vote in the House, where Republicans hold a 220-212 majority, is likely to be close.

"It's a great bill. There is something for everyone," Trump said at an event in Florida on Tuesday. "And I think it's going to go very nicely in the House."

An initial version passed with only two votes to spare in May, and several House Republicans have said they do not support the Senate version, which the nonpartisan Congressional Budget Office estimates will add US$800 billion more to the national debt than the House version.

Republicans have struggled to balance conservatives' demands for deeper spending cuts to reduce the impact on the deficit with moderate lawmakers' concerns that the Medicaid cuts could hurt their constituents, including service cutbacks in rural areas.

The House Freedom Caucus, a group of hardline conservatives who repeatedly threatened to withhold their support for the tax bill, has criticised the Senate version's price tag.

"There's a significant number who are concerned," Republican Representative Chip Roy, a member of the Freedom Caucus, said of the Senate bill.

A group of more moderate House Republicans, especially those who represent lower-income areas, have objected to the steeper Medicaid cuts in the Senate’s plan. (Reuters)