WASHINGTON – President Obama and congressional Republicans on Wednesday began hurtling toward an unpredictable collision over the federal budget, as the House of Representatives planned to vote to strip money from the national health-care law while the White House readied plans for a government shutdown.

That vote in the Republican-dominated House, expected later this week, will set the stage for a spending showdown likely to last for days. Next week, the House plans to unveil another measure aimed at delaying the law. The new federal fiscal year begins Oct. 1, and unless Congress and Obama agree on a budget, much of the government will be out of business.

The new Republican plan, announced Wednesday, would finance the government but also defund implementation of the 2010 health-care law. That’s expected to pass the House but stall in the Democratic-led Senate.

That’s the scenario for stalemate. White House spokesman Jay Carney said Wednesday that the administration would not accept any delays to the health-care law to avoid a shutdown.

The House plan is likely to be phase one of a weeks-long clash over the federal budget as Democrats look to keep the government open, restore spending cuts known as the sequester, and raise the debt ceiling to allow the government to borrow to pay bills already approved by Congress and incurred.