The White House says President Barack Obama would veto House Republican legislation that would delay much of the president's health-care overhaul for a year and cancel a tax on medical devices.

The White House statement comes as the Republican-run House prepares to debate a bill averting a government shutdown Tuesday morning, but delaying the health-care law and repealing the tax as the price for doing so. The medical-device tax helps finance the health-care law.

The Democratic-run Senate has approved legislation preventing the shutdown and leaving the health-care overhaul alone. That 2010 law, widely known as Obamacare, has been Obama's proudest domestic achievement.

The White House says the House bill would advance a narrow ideological agenda and threaten the economy. It says the bill pushes the government toward a shutdown.

Undeterred, House Republicans pledged to press ahead with their latest attempt to squeeze a concession from the White House in exchange for letting the government open for business normally on Tuesday. They also agreed to pass legislation assuring U.S. troops are paid in the event of a shutdown.

"I think we have a winning program here," said Republican representative Hal Rogers, chairman of the House Appropriations Committee, after days of discord that pitted Speaker John Boehner and his leadership against Tea Party-backed conservatives.

US debt ceiling

U.S. House Speaker John Boehner playfully pumps his fist as he arrives at the Capitol in Washington on Saturday. House Republicans remain under Tea Party pressure to use a must-do funding bill to derail President Barack Obama's health-care law. (Jonathan Ernst/Reuters)

Democratic senator Patty Murray, who heads the Senate Budget Committee, accused the House Republican leadership of "pandering to the tea party minority."

Apart from its impact on the health care law, the legislation that House Republicans decided to back would assure routine funding for government agencies through Dec. 15.

The measure marked something of a reduction in demands by House Republicans, who passed legislation several days ago that would permanently strip the health-care law of money while providing funding for the government.

The Senate rejected that measure on a party-line vote of 54-44 Friday, insisting on a straightforward continuation in government funding without health care-related add-ons.

That left the next step up to the House — with time to avert a partial shutdown growing ever shorter.

Senate majority leader can block delay

For a moment at least, the revised House proposal papered over a simmering dispute between the leadership and Tea Party conservatives who have been more militant about abolishing the health law that all Republicans oppose.

It was unclear whether members of the rank and file had consulted with Texas senator Ted Cruz, who has become the face of the "Defund Obamacare" campaign that Tea Party organizations are promoting and using as a fundraising tool.

Instead, House Republican moderates and conservatives said it soon would be up to Senate Majority Leader Harry Reid of Nevada and fellow Democrats to decide whether the government would remain open past the shutdown deadline of midnight Monday.

Asked if the House measure would risk a shutdown, Republican representative Mo Brooks of Alabama said, "It depends on how long.... Reid wants to continue to be financially irresponsible and obstructionist."

Republican representative Charles Dent of Pennsylvania said, "Once this passes the House, the Senate's going to have to make a decision. Will they move quickly or will they dawdle?"

Left unspoken was how the House would respond if the Senate rejected the measure and insisted once more on a bill with no extraneous items.

There was little doubt that Reid had the votes to block a one-year delay in the health care program.

It appeared the Republicans' chances of winning a concession centred on the medical device tax, which was incorporated into the health law to help pay its costs. Some Republicans noted that the Senate has taken a nonbinding 79-20 vote to repeal the levy, and that several members of Obama's party supported the proposal.

In fact, the total was more than half the Democratic senators, 33 in all. Those in favour included members of the leadership, Sens. Dick Durbin of Illinois and Chuck Schumer of New York among them, as well as Murray.

Federal programs face cutoff

"What will move this is if there are other Democratic senators who put pressure on Reid," said Republican Rep. Richard Hudson of North Carolina.

'I've got a titanium backbone. Let 'em blame, let 'em talk, it's fine.' - Republican representative Marsha Blackburn, Tennessee

The 2.3-per-cent tax, which took effect in January, is imposed on items such as pacemakers and CT scan machines; eyeglasses, contact lenses, hearing aids and other items are exempt. Repealing it would cost the government an estimated $29 billion over the coming decade.

Some Republicans breathed defiance, despite fears inside the party that the Republican Party would bear the blame for any interruption in government services.

"I've got a titanium backbone. Let `em blame, let `em talk, it's fine," said Republican representative Marsha Blackburn of Tennessee. She said the GOP wanted to keep the government open, but also wanted to reduce its size and "delay, defund, repeal and replace Obamacare," as the health law is called.

Despite such claims, House Republicans have yet to offer a replacement measure for the law they have pledged to repeal. They first promised to do so three years ago, during the 2010 election campaign when they wrested a majority from the Democrats.

If lawmakers miss the approaching deadline, a wide range of federal programs would be affected, from the national parks to the Pentagon.

Some critical services, such as patrolling the borders, inspecting meat and controlling air traffic, would continue. Social Security benefits would be sent and the Medicare and Medicaid health care programs for the elderly and poor would continue to pay doctors and hospitals.

The new health insurance exchanges would open Tuesday, a development that's lent urgency to the drive to use a normally routine stopgap spending bill to gut implementation of the law.