A total 221 Republicans in the United States House of Representatives are to vote on the replacement of the ousted speaker on Wednesday morning.

It will be a choice between Majority Leader Steve Scalise and Judiciary Committee chairman Jim Jordan who both faced a two-hour candidate forum by their conservative party on Tuesday.

Scalise told his partymates in the private meeting he could lead them out of speakership crisis that has prevented congressional action on the Israel crisis and other urgent business.

The majority leader touts himself as a unifier and coalition builder.

"We need a Congress that's working tomorrow, we need to get Congress back to work," he told reporters in Washington.

Jordan, meanwhile, has the coveted endorsement of former President Donald Trump and is a darling of the right.

The speakership contest has taken on a heightened sense of urgency in the wake of the bloodshed in Israel, which left more than 1,500 dead in the worst attack in the country's 75-year history. Another 900 people have been killed in Gaza, officials say.

US President Joe Biden has pledged help, and Democrats have been pushing for emergency aid to be wrapped into a broader Ukraine-focused funding package being prepared in the Senate.

Almost 400 lawmakers introduced a symbolic resolution standing with Israel, and a separate group drafted bipartisan legislation to expand the White House's power to sanction Hamas.