The opposition has sought leave in parliament to have federal Speaker Peter Slipper removed from his office.
Liberal leader Tony Abbott asked that under section 35 of the constitution the Speaker 'be removed from office immediately'.
'It's clear that this Speaker is no longer a fit and proper person to uphold the dignity of the parliament,' Mr Abbott said, adding he was taking a 'rare and unusual step'.
Earlier, Prime Minister Julia Gillard said she wouldn't comment on crude text messages allegedly sent by Mr Slipper because the matter was before the courts.
Mr Abbott opened question time on Tuesday with his bid to suspend normal business to call for Mr Slipper to be removed immediately.
He said Mr Slipper was disqualified from high office, not because of the legal action on foot against him.
'He is disqualified because of the undenied, uncontradicted facts that have emerged in the course of this case,' he said.
'There are the truly gross references to female genitalia. I regret to speak in this way to this House but it is necessary to prosecute this matter.'
Mr Abbott said Mr Slipper had failed the character test and the prime minister had failed the judgment test.
'This prime minister has failed the judgment test when it came to the member for Dobell (Craig Thomson), now she has failed the judgment test when it comes to the Speaker of this parliament,' Mr Abbott said.
'For months and years this prime minister ran a protection racket for the member of Dobell, please, please, let's not have the same protection racket run for the benefit of the current Speaker of this parliament.'
Mr Thomson, who resigned from the Labor party, is linked to the HSU funds scandal.
Before question time, Mr Abbott had called Mr Slipper's position 'untenable' following the release of text messages between the Speaker and staffer James Ashby, who has accused Mr Slipper of sexual harassment.
The messages came to light in documents filed in the Federal Court in Sydney.
Mr Abbott told parliament on Tuesday a text from Mr Slipper about female genitalia was gross.
He said Mr Slipper had showed a clear bias against a member of the parliament, referring to text messages about Liberal MP Sophie Mirabella.
'I must allude to the vile anatomical references to which this Speaker appears to be addicted in his text message,' he said.
Mr Abbott said it was the Speaker's role to uphold the standing orders of the House of Representatives impartially.
He said Mr Slipper had failed to do that when he referred to Ms Mirabella as an 'ignorant botch (sic)' when she was thrown out of the House of Representatives on the day of the carbon tax vote in October last year.
Mr Abbott said Ms Gillard should be ashamed of herself and her judgment for appointing Mr Slipper as Speaker.
'Should she rise in this place now to try and defend the Speaker, to try and say that she retains confidence in this Speaker, she will shame this parliament again,' he said.
'And every day the prime minister stands in this parliament to defend this Speaker will be another day of shame for this parliament, another day of shame for a government which should already have died of shame.'
Deputy Opposition Leader Julie Bishop unsurprisingly backed the motion.
She said she would struggle to show respect to Mr Slipper if he returned.
'How (are) the women in this house expected to show respect to the Speaker?' Ms Bishop asked.
'While I do not presume to speak for all the female colleagues on either side of the chamber, I would personally struggle to show appropriate respect.'
Ms Bishop said Mr Slipper was the prime minister's choice of Speaker.
She said Ms Gillard struggled to admit mistakes but this issue went beyond the prime minister's pride.
Mr Slipper would be an embarrassment to the parliament if he were allowed to remain, Ms Bishop said.
If members of the parliament lost respect for the Speaker, the public would too, she said.
