The coalition could break up before its five-year term is over, Business Secretary Vince Cable has said.
Ministers have previously insisted the Tory-Lib Dem pairing would last until the 2015 election campaign begins.
Asked at a Lib Dem conference fringe event if a separation could occur a few months before polling day, the party MP said: "It's certainly possible."
But he added "we have not yet had those conversations" and the process would have to be led by leader Nick Clegg.
A source close to Mr Cable later told the BBC the business secretary was committed to the coalition programme in government and would see it through.
But Mr Cable's answers to journalists' questions at the conference fringe event organised by the Independent newspaper were a departure from the stated position of ministers and senior party figures.
"It is obviously a very sensitive one. It has got to be led by the leader," he said.
"We have not yet had those conversations. They are important."
Asked later on the BBC's Newsnight programme if the coalition could end in 12 months' time, Mr Cable said: "All kind of things were possible but I'm not going to able to give you any useful information on that."
He said the time to end the coalition was "something that has to be collectively decided by our Lib Dem team as we get much closer to the time".
Separately, party president Tim Farron told a fringe meeting at the Lib Dem conference in Glasgow that something "apocalyptic" would have to happen to end the partnership early.
"I don't know what exactly will happen, but my view has always been the coalition lasts five years, end of story," he said.
BBC political correspondent Ross Hawkins says questions about the end of the coalition are set to be repeated as the date of next general election draws closer.
In the past, when asked whether the partnership could survive the political rigours ahead of a general election campaign, Lib Dems have tended to stress that they plan to see the government through, our correspondent adds.
In a briefing ahead of the conference, Lib Dem education minister David Laws said the coalition with the Conservatives would last "right up to the wire".
And in May, Mr Clegg said he "could not envisage any circumstances" in which there would be an early election.
Prime Minister David Cameron, meanwhile, said maintaining the coalition remained the best course of action to address "big picture" issues such as the economy.
Earlier, Mr Clegg denied suggestions of a rift with the business secretary over the party's economic policy.
Mr Cable had been expected to miss a key conference debate on deficit reduction.
In the end he arrived in the conference hall one hour into the debate and voted for the leadership's position - although he did not sit alongside his party leader and other ministers.
But in his conference speech, Mr Cable accused his Conservative coalition partners of "ugly" and "blinkered" politics.
Attacking Tory policies on immigration, the economy and Europe, he said their approach was based on the "cynical" calculation that "fear trumps hope" and "competence requires callousness".
Mr Cable told Newsnight he believed the Lib Dems should highlight the "positive things" the coalition had done as well as criticising the Tories "when they go over the top".