Federal police have raided the Department of Home Affairs office in Canberra, as officers investigate a leak related to the au pair saga.
Internal emails leaked to the media showed minister Peter Dutton's office demanded an au pair detained at Brisbane airport be given urgent consideration for a visa, preferably within an hour.
Mr Dutton told parliament last month he did not know the people she was planning to work for.
It was later revealed her intended employer was an old Queensland Police colleague of Mr Dutton's, Russell Keag, who emailed the minister's office to say it had been a "long time between calls".
Mr Dutton said he had not spoken to Mr Keag in 20 years before he was approached for help with the visa.
The emails also show the department expressly disagreed with Mr Dutton's push to give a visa to another au pair detained in Adelaide in November 2015.
He also intervened after AFL boss Gillon McLachlan got his office to contact Mr Dutton's office to ask for help.
Asked about Thursday's raids, an AFP spokesman told AAP it had received the Home Affairs leak referral on August 30.
"The matter has been accepted for investigation," the spokesman said.
"The AFP has undertaken enquiries and conducted a number of activities in relation to this investigation."
The AFP is expected to hand any seized material to the Clerk of the Senate, as Labor senator Louise Pratt on Thursday claimed parliamentary privilege over it.
Senator Pratt said the material was relevant to an inquiry she chairs.
"Parliamentary privilege is an incredibly important principle that enables the parliament to hold the government to account, and it must be respected," she said in a statement.
The Senate's privileges committee will determine whether the senator's privilege claim should be upheld.
Labor justice spokeswoman Clare O'Neil said Mr Dutton himself had serious questions to answer over the au pair issue and should not be pursuing whistleblowers.
"What I don't want to see here is ... the Home Affairs Minister taking action against people who are divulging information that's probably in the public interest, when it's him that has a case to answer," she said.
Liberal MP Michael Sukkar said the leak inquiry was important.
"Whether it is a Liberal government or a Labor government, they need to have confidence that public servants are treating information appropriately and it is very important that if there are breaches of those rules that they are followed up," Mr Sukkar told Sky News.
© AAP 2018