Labour deputy leader Harriet Harman has called Nick Clegg's response to the allegations against Lord Rennard "a cop out" and claimed the women who made the complaints are "being hung out to dry".
Ms Harman said: "The Lib Dem women who complained about Lord Rennard did a brave thing in coming forward and making an official complaint. But now they are being hung out to dry and accused of suffering from 'distress'.
"They have complained about inappropriate behaviour but Clegg says unless proved beyond reasonable doubt - ie that Rennard committed a criminal offence - the Lib Dems can take no action. This is a cop out.
"Nick Clegg must get off the fence otherwise it will send out a signal to any woman who suffers sexual harassment that she needn't bother to complain."
Former Liberal leader Lord Steel has told ITV News the party is in an "awful mess" over the Rennard row and it needs "to get a grip" of it.
Lord Rennard has threatened to take legal action after being suspended for refusing to apologise over sexual harassment allegations.