Lib Dem leadership hopeful Jo Swinson has said she would consider a coalition with Labour or the Tories.
Ms Swinson, currently the party's deputy leader, said there is no immediate prospect of the Lib Dems becoming allied with either the Tories and Labour as both are “led by Brexiters”.
But she said that she would "not say never" in the future.
In an interview with The Herald newspaper, she said: "I have not said never in any future scenario, where things are different.
"I'm looking at the situation right now in terms of being led by Brexiters on both sides.
"The same holds for confidence and supply. We need to stop Brexit and work with people who agree with us on that, and that's not the leadership of the Conservatives or the Labour Party."
The Liberal Democrats deputy leader, who is running against Sir Ed Davey to succeed Sir Vince Cable in the party's top job, would become the first female leader of the party if she wins the leadership race.
She also said she believes at present the party has its best chance to fundamentally change British politics.
"We have had in our history of the Liberal Democrats and predecessor parties, various points at which it has been tantalising close to totally breaking the mould of British politics; during the 1980s," she said.
"We have an even better opportunity now and that's what we absolutely do need to grab hold of."
The 39-year-old said this is "ambitious" and she does not "underestimate" the challenge the Lib Dems would face to boost their 12 MPs by 300 to form the next government.
In the wide-ranging interview, Ms Swinson also addressed the issue of Scottish independence.
She claimed the SNP does not have a mandate for a second independence referendum as the 2014 ballot, based on the nationalists' vision outlined in the white paper Scotland's Future, was rejected.
Meanwhile, her leadership rival claimed the "SNP is not either for the Scottish people or the United Kingdom".
Speaking on the BBC Scotland's Good Morning Scotland radio programme, Sir Ed Davey said: "We reject nationalism per se. We believe think it divides people unnecessarily.
"That's why we believe that the SNP is not good either for the Scottish people or for the United Kingdom, and we believe Britain should stay in the EU."
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Asked if his leadership prospects have been damaged by his prominent role in the Conservative-Liberal Democrat coalition, during which he was Energy Secretary, the Kingston and Surbiton MP said this was not the case.
He said: "No, because I fought the Tories day in, day out.
"We stopped them putting even heavier welfare cuts, we stopped them cutting education."
