Jeremy Corbyn urged to prove he has backing to be PM
Jeremy Corbyn has been urged to prove he has enough backing from MPs before the Liberal Democrats support his bid to become temporary prime minister.
Opposition parties want to try and bring down the government to stop a no-deal Brexit.
Labour leader Mr Corbyn wants MPs to vote to make him caretaker prime minister.
But new Brecon and Radnorshire MP Jane Dodds said he must prove he has enough backing from Conservatives first.
Liberal Democrat leader Jo Swinson believes Tory Ken Clarke or Harriet Harman would have more backing from MPs to take on the role.
However, Ms Dodds said: "He needs to say 'I have the eight Conservatives that are needed, these are their names, they are prepared to see me as PM' and put them forward.
"If he has the numbers, let's see them."
Prime Minister Boris Johnson plans to take the UK out of the EU on 31 October without a deal if a new one is not negotiated.
Opposition parties in the Commons plan to call a vote of no confidence when they return from their summer break in September and want to use the support of rebel Tories to bring down his government.
Aberconwy Tory MP Guto Bebb has urged his party members to "take seriously" Mr Corbyn's proposals.
But Ms Swinson has put forward Mr Clarke and Labour's Ms Harman - who are the longest continuously-serving male and female MPs - as potential caretakers.
Ms Dodds said the party has written to Mr Corbyn and said "we will get behind you" if he proves he has the support and sets out a clear plan.
However, she does not believe he could muster the necessary levels.
"We have one opportunity to form a government of national unity - time is running out - it needs to be absolutely right," Ms Dodds told BBC Radio Wales' Sunday Supplement.
"It needs to be someone with authority to take people forward so on 31 October we don't crash out of Europe.
"Whoever is able to be in that position of authority to command numbers and authority, we will back them."
Calling the situation an "emergency", she suggested Mr Clarke would command credibility across the Conservative Party, adding: "This is something Jeremy Corbyn or Jo Swinson could not do."