AUSTRALIAN Prime Minister Julia Gillard has dismissed as "disgraceful" claims she was making light of sexual harassment by allowing the parliamentary speaker to keep his job while facing allegations he pressured a member of staff for sex.

House of Representatives Speaker Peter Slipper stepped aside on Sunday while police investigate allegations he misused taxi payment vouchers while travelling by limousine in Sydney this year.

The member of staff, James Ashby, 33, is also suing Mr Slipper in the Federal Court for sexual harassment, alleging he only employed him as a media adviser in pursuit of sex.

Mr Slipper, 62, who is married with two adult children from a previous relationship, denies the allegations.

Opposition leader Tony Abbott has said both the criminal investigation and the civil case should be resolved before Mr Slipper returns to the speaker's chair. Ms Gillard "is essentially making light of sexual harassment" by arguing Mr Slipper could serve as speaker while facing the civil charges, Mr Abbott said.

She responded saying: "That's a disgraceful allegation and it's exactly what we expect from Mr Abbott: Continued negativity."

The Government argues that while senior officials should stand aside while facing criminal charges, there was no precedent for them to do so in the face of civil suits.