WASHINGTON (REUTERS) - US Senator Mitt Romney, a leading Republican critic of former president Donald Trump, will help raise money for Representative Liz Cheney, who is fighting for political survival after voting to impeach Trump and contesting his false stolen-election claims.

Romney is the featured guest at a March 14 fund-raiser for Cheney at the home of Bobbie Kilberg, a well-connected Virginia Republican who lined up against Trump during his 2016 bid for the White House, according to an invitation seen by Reuters.

In addition to Romney, the list of attendees is comprised of an array of establishment Republican figures and Trump critics, including former congresswoman Barbara Comstock, former Homeland Security secretary Michael Chertoff, lobbyist Charlie Black, and former vice-president Dick Cheney, Liz Cheney's father.

The event comes as Liz Cheney gears up for a tough primary battle for Wyoming's only congressional district in August against a lawyer, Harriet Hageman, endorsed by Trump. The race, which will almost certainly determine the general election winner in the deeply conservative state, is widely seen as a proxy for the former president's grip over the Republican Party.

Cheney has been the target of Trump's ire and sidelined by most Republicans after voting last January to impeach Trump on a charge that he incited an insurrection at the US Capitol on Jan 6, and helping lead an ongoing congressional committee investigating the attack.

Last year, Republicans voted to remove Cheney from her leadership position in the US House of Representatives.

Cheney is not in financial trouble, having ended September with more than US$3.6 million (S$4.8 million) in the bank. But she faces a challenge for survival in Wyoming, where the activist base of her own party has moved against her. Over the weekend, Cheney won only six votes in a straw poll conducted by the Wyoming Republican State Central Committee, with Hageman securing 59.

Billionaire Peter Thiel and Donald Trump Jr were scheduled to co-host a pair of fund-raisers for Hageman on Wednesday, Politico reported last month. Hageman had roughly US$245,000 in the bank as of September.