Business Secretary Vince Cable today denied that he or Nick Clegg knew about strongly-denied allegations of inappropriate behaviour towards women by a senior Liberal Democrat.
Mr Cable said the claims about the party's former chief executive Lord Rennard were being taken "very seriously" and would be fully investigated.
But pressed on whether he was aware of complaints against the peer before a Channel 4 News report on Thursday, he replied: "Absolutely not."
He told the BBC's Andrew Marr Show: "Nick Clegg has also said he was not aware of these allegations until they appeared on TV last week. But they are serious, and we take them very seriously.
"It is obviously wrong if there are women there who have made complaints and felt they haven't been dealt with properly."
Lord Rennard - a key party strategist and adviser to a succession of Lib Dem leaders before standing down due to ill health in 2009 - has said he is "deeply shocked" by the allegations, which he "strongly disputes" and regards as a "total distortion" of his character.
Lib Dem leader Mr Clegg is facing questions about his knowledge of the situation after the Mail on Sunday published a Facebook discussion of the claims from January 2009.
One party worker, said to have made a complaint against Lord Rennard, wrote: "I just don't know how Nick can know and not do anything."
Current Lib Dem chief executive Tim Gordon admitted last night that it appeared the party "did not fully live up to our political ideals" in dealing with complaints about the peer.
Mr Cable said he was not aware that there was any reason for Lord Rennard stepping down in 2009 other than health issues.
"As far as I am concerned, and I am sure as far as Nick Clegg was concerned, this was an issue of him standing down because of health," he said.