Nick Clegg was only recently made aware of the allegations of sexual harassment surrounding the party's former chief executive, the Liberal Democrats have insisted.
Aides said the Deputy Prime Minister only learned about the complaints being made against Lord Rennard following a Channel 4 News report earlier in the week.
Several women accused the peer of inappropriately touching and propositioning female party workers, which he strenuously denies.
The women claimed they reported Lord Rennard's behaviour to senior party officials at the time, but no further action was taken.
And the Mail On Sunday reported that one of the women who came forward to the Channel 4 programme had discussed the allegations with a friend on Facebook as long ago as January 2009.
"I just don't know how nick can know and not do anything.. :-( makes me very sad," she is said to have written.
Her friend apparently replied: "Unless women come forward and go through a formal process ... there isn't much Nick can do."
A Lib Dem spokesman said he had no idea why the Facebook comment had been made, adding: "Nick Clegg only knew of these allegations when we were contacted by Channel 4 News."
Mr Clegg has been on holiday on Spain since the story broke, but is likely to be asked to respond in person as the party launches an investigation into the matter.
Lib Dem Jeremy Browne told Sky News' Murnaghan programme he had known Lord Rennard for 20 years but had not heard "gossip" or the specific allegations before - and said the same applied to Mr Clegg.
He said the party would look at bringing in independent figures to ensure the its investigations are open and transparent.
He said: "My understanding is that what we're doing initially is bringing on the people within the party's structures who have obvious expertise and a record of integrity within the party.
"But if we can introduce an independent element, people who are not Liberal Democrat members but could lend us their expertise in looking at how we can have the best procedures, then that may give people even more confidence."
Business Secretary Vince Cable was asked on the BBC's Andrew Marr Show whether he knew about the Lord Rennard allegations prior to the Channel 4 programme, and replied: "Absolutely not."
Equalities minister Jo Swinson - a former parliamentary aide to Mr Clegg - has said she "took action" after some women confided in her, but she has not been specific about what she did. She said she welcomed the review so that "lessons can be learned".
The development came as current Lib Dem chief executive Tim Gordon said it appeared the party "did not fully live up to our political ideals" in dealing with the complaints about Lord Rennard.
The peer was a key party strategist and adviser to a succession of Liberal Democrat leaders before standing down due to ill health in 2009.
He said he was "deeply shocked" by the allegations, which he "strongly disputes" and regards as a "total distortion" of his character.
The Lib Dems have launched an internal investigation into the specific allegations against him under the party's disciplinary procedures.
Party president Tim Farron is also conducting a review into the way the party deals with such allegations.