Opposition Leader Tony Abbott has urged independent federal MP Craig Thomson to co-operate fully with police after a raid on his NSW home.
Mr Abbott also praised police for their work in the case.
'I think it's very important this member of parliament fully co-operates with police,' Mr Abbott told reporters in Adelaide on Wednesday.
'The police have shown a lot of diligence in trying to ensure that low paid workers' money is not misused.'
Mr Abbott said he wished the same diligence in the Craig Thomson affair had been shown by the federal government.
'Lets not forget it was the prime minister who was saying for months and years that she had full confidence in Craig Thomson,' he said.
His comments followed the raid on Wednesday morning on Mr Thomson's home on the NSW central coast.
Media reports said officers raided the Bateau Bay property shortly after 7am (AEDT).
NSW police are believed to have obtained the warrant on behalf of Victorian police.
They are investigating allegations Mr Thomson improperly used Health Service Union (HSU) funds to spend on prostitutes, air travel, entertainment and cash withdrawals in excess of $100,000.
Officers are believed to have seized computers from Mr Thomson's home, with the material to be taken back to Victoria, the Seven Network said.
Last week Fair Work Australia (FWA) launched civil action against Mr Thomson alleging he breached workplace laws 37 times and misused almost $500,000 when he was national secretary of the HSU from 2002 to 2007.
The former Labor MP, now an independent, faces fines of up to $450,000 if the court finds, amongst other things, he spent thousands of dollars of union funds on prostitutes.
Mr Thomson has maintained his innocence and says the case won't go anywhere.