Former Lib Dem leader Paddy Ashdown has backed acting leader Sir Menzies Campbell to succeed Charles Kennedy.
Lord Ashdown said Sir Menzies, who says he wants to restore "a sense of purpose and unity", was the right person to take the party forward.
Sir Menzies is the only candidate so far but Lib Dem MP Phil Willis says he may challenge him if no-one else does.
Party president Simon Hughes and home affairs spokesman Mark Oaten are yet to decide whether to enter the race.
The party's federal executive is meeting to draw up a timetable to elect the new leader on Monday evening.
Under proposals to be discussed at the meeting, the new leader would be in place by the end of March.
Nominations would open immediately and close in early February. Ballot papers would be sent to members in late February with voting in March, turning the Lib Dem spring conference into a hustings event.
Mr Kennedy resigned on Saturday, days after admitting he had a drink problem.
His resignation came after 25 MPs said they would refuse to serve under him.
'Man of substance'
Sir Menzies has the backing of more than a third of Lib Dem MPs, plus grandees including Lord Ashdown.
Lord Ashdown told BBC Radio 4's Today programme: "At the next election he'll offer the British public an alternative that provides weight and substance and seriousness in a political debate that is, frankly, increasingly obsessed with modishness and flim-flam."
Some have suggested Sir Menzies, 64, is too old but Lord Ashdown argued his talents far outweighed other factors.
And he said that although a leadership election would probably be good for the party, people should not be "forced" to stand.
Sir Menzies refused to answer questions about his leadership hopes on Monday, saying he was focusing on his current role as deputy leader.
He told reporters outside his Edinburgh home: "My objective is to restore a sense of purpose and unity, particularly with the local government elections ahead."
Some of Sir Menzies' backers hope the party can unite around one candidate in a "coronation" - similar to the one in which Michael Howard became Conservative leader in 2003.
But Mr Kennedy has said a contest is needed so members could have "direct input" after feeling "shut out" of his departure as leader.
Mr Oaten said he had received many positive e-mails and was "toying" with the idea of contesting the leadership and he would say whether he would stand on Tuesday.
He said there should be a contest of some kind as members were feeling "pretty excluded from the process so far".
Mr Hughes, the party president, says he will reveal his intentions within the next week.
And Mr Willis said he wanted to make sure a small group of MPs did not feel they could remove one leader and appoint a new one without consulting ordinary members.
He said: "If it meant I had to stand there would be an election, come what may."
New Lib Dem MP John Hemming is trying to get enough support to stand if Mr Oaten and Mr Hughes do not challenge Sir Menzies.
A member of the party's federal executive, Peter Black, said ordinary members felt disenfranchised by the way Mr Kennedy had been toppled.
They could continue to be disenchanted if there was no leadership contest, he said.