Top Republican Kevin McCarthy said on Sunday that he expects to fend off a challenge to his speakership after a leading hardline Republican indicated that he would move to oust him for striking a deal with Democrats to avert a US government shutdown without the spending cuts demanded by the right-wing caucus.

"I do intend to file a motion to vacate Speaker McCarthy this week," Congressman Matt Gaetz told CNN. "I think we need to rip off the Band-Aid."

"I'll survive", McCarthy told CBS. "This is personal with Gaetz."

Gaetz is a leading figure within the House Freedom Caucus – a small group of hardline Republican legislators who had brought the government to the brink of shutdown with their refusal to adopt fresh federal funding without deep spending cuts.

The group was furious when McCarthy struck a stopgap deal with Democrats late Saturday to keep the government open for a further 45 days at current spending levels.

"I think we need to move on with new leadership that can be trustworthy," Gaetz told CNN but said it was unclear that the group could actually remove the speaker, especially after McCarthy turned to Democrats to pass the bipartisan bill.

He pointed out that "the only way Kevin McCarthy is speaker of the House at the end of this coming week is if Democrats bail him out."

"Go ahead and try," McCarthy urged on Saturday, addressing his opponents. "You know what? If I have to risk my job for standing up for the American public, I will do that."

It is noteworthy that the Republicans enjoy a slight 221-212 majority in the House of Representatives. It is still unclear how many votes McCarthy would receive in such a vote, or whether any Democrats would support him, especially since the speaker enraged Democrats last month when he launched an impeachment probe on President Joe Biden.

Gaetz is one of approximately two dozen hardliners who forced McCarthy to undergo 15 rounds of voting before he was elected speaker in January, during which they obtained concessions such as a rule change that allows any House member to ask for a vote to impeach the speaker.

Pro-McCarthy Republicans will also work to prevent his ouster. Republican Mike Lawler told ABC's This Week on Sunday that "the only responsible thing to do was to keep the government open and funded while we complete our work."

"By putting this motion to vacate on the floor, you know what Matt Gaetz is going to do? He's going to delay the ability to complete that work over the next 45 days," Lawler said.

On her part, Democratic Representative Alexandra Ocasio-Cortez said her party was doubtful to facilitate McCarthy preserve his job unless Republicans made compromises.

"I don't think we give up votes for free," Ocasio-Cortez told CNN.

"Would I cast that vote? Absolutely. Absolutely. I think Kevin McCarthy is a very weak Speaker. He clearly has lost control of his caucus," she said when asked if she would vote to remove McCarthy.

If Congress had failed to keep the government open, the closures would have begun just after midnight (0400 GMT Sunday) and would have delayed salaries for millions of federal employees and military personnel.

Among other immediate effects, the majority of national parks would have been shuttered to the public from Sunday.