Donald Trump on Wednesday called for far-right Republicans to end their blocking of the party's candidate to become US House speaker, after a damaging split prevented Kevin McCarthy from securing the key role.

Congress was thrown into disarray on Tuesday by the rebels' move to derail McCarthy's candidacy, with the House of Representatives failing to elect a speaker for the first time in a century.

Rather than celebrating their new control of the lower chamber, the Republican Party has instead been pitched into a drawn-out public fight that put McCarthy's political career on the line.

"It's now time for all of our great Republican House Members to vote for Kevin, close the deal and take victory," Trump posted on social media.

"Republicans, do not turn a great triumph into a giant and embarrassing defeat."

McCarthy needed 218 votes in the House, which flipped to a narrow 222-212 Republican majority after last year's midterm elections.

But he failed to bring into line the party rebels, including several high-profile allies of former president Trump, and he was rocked by 19 "no" votes from his own side in each of the first two rounds, rising to 20 in the third.

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The House was adjourned on Tuesday and was expected to hold further ballots on Wednesday until someone emerges with a majority -- and it is not out of the question that a new candidate could come to the fore.

One roadblock to McCarthy's anointment was the perception by some on his party's right wing that he is insufficiently loyal to Trump, who is running for the White House again after losing to Joe Biden in 2020.

McCarthy, who defied a subpoena from the special House panel probing the 2021 assault by Trump supporters on the Capitol, has already promised the hardliners investigations of Biden's family and administration, as well as of the FBI and CIA.

But the more he is seen as giving in to the right, the more likely he is to alienate moderates.

His performance was so weak that he lost out to the Democratic minority leader Hakeem Jeffries in each of the opening three ballots -- although there remains little doubt a Republican will ultimately claim the speaker's gavel.

The last time it took more than one round of voting to pick a speaker at the start of a new Congress was a century ago, in 1923. Another historic speaker selection process that began in December 1855 took 133 rounds of voting over two months.

"It's time to celebrate, you deserve it," Trump said. "Kevin McCarthy will do a good job, and maybe even a great job -- just watch!"

The Speaker wields huge influence in Washington by presiding over House business and is second in line to the presidency, after the vice president.