Tom Brake said veteran MPs Ken Clarke and Harriet Harman have “more potential” than Jeremy Corbyn to lead an emergency government.
The Liberal Democrat Brexit spokesman told talkRADIO’s Julia Hartley-Brewer that to prevent a no-deal Brexit, a coalition must be led by someone “above the fray”.
He added: “It’s not an issue about Jeremy Corbyn, it’s an issue about who can command the most support.”
According to his party leader Jo Swinson, Mr Clarke and Ms Harman are ready to "put public duty first".
She said they had assured her they are prepared to lead an emergency government to stop the country withdrawing from the EU without a deal.
Discussions over emergency leadership began after Mr Corbyn made a bid to be installed as a caretaker Prime Minister in the run-up to a general election, should he win a vote of no-confidence in the government.
Mr Brake has reiterated his party’s stance against ever supporting a Corbyn leadership, just as Ms Swinson ruled out working with Boris Johnson when she was appointed last month.
The Carshalton and Wallington MP said: “Unfortunately we’re blessed with two party leaders who, I think, are frankly not fit for the roles they’re holding”.
However, Ms Swinson has suggested meeting with Mr Corbyn to discuss preventing a no-deal, despite dismissing his plan.