But it says the ball is in the Finance Department's court. Speaker Bronwyn Bishop must produce the documents claiming the chopper excursion expenses. Credit:Andrew Meares "There is a protocol – the Minchin Protocol – which was established in 1998 to handle complaints regarding the use of entitlements by federal parliamentarians," and AFP spokesman said. "This is the agreed protocol for dealing with matters of this nature." Under the protocol – named after former finance minister Nick Minchin – the department will conduct an internal audit to determine whether the allegations are credible. If it decides there has been serious and deliberate wrongdoing it can refer the case back to the police.

But it's understood Labor is not happy with the AFP's response and will write to it again on Saturday asking for clarification. Bronwyn Bishop arrives by helicopter at a golf course for a Liberal fundraiser. Credit:Twitter @neilremeeus Prime Minister Tony Abbott is expected to make his first public comments about the scandal later on Saturday. But Fairfax Media understands he is standing by his Speaker. At a closed door event on Friday Mr Abbott reportedly dismissed the scandal as "village gossip". However the Prime Minister's office says that was not an accurate reflection of what he said. Prime Minister Tony Abbott is expected to make a statement on Bronwyn Bishop on Saturday. Credit:James Brickwood

Coalition ministers and MPs are quietly furious that the scandal has derailed their attacks on Labor over union corruption, and some have described her position as increasingly untenable. But Finance Minister Mathias Cormann says he strongly disagrees with that assessment. "From where I sit Bronwyn Bishop is doing a very good job as Speaker," he told Sky News on Saturday. "The key here is the Speaker has reimbursed the claim."



Mrs Bishop caved to political and public pressure and paid back the money, along with a $1300 fine, but has admitted no wrongdoing. Labor believes the case hinges on whether Mrs Bishop signed a Presiding Officer's Charter Certification form. The form requires the Speaker to confirm that a charter is for her "office holder duties" and states that knowingly giving false or misleading information is a serious criminal offence. Senator Cormann said he would have no oversight or involvement with his department's investigation.

Independent senator Nick Xenophon hopes the "choppergate" scandal will be a catalyst for broader changes to entitlements. He wants greater transparency and an independent umpire to deal with complaints. He also wants tougher penalties when mistakes are made. Labor wrote to the AFP shortly after Fairfax Media exclusively revealed that the political lobbyist who was paid to arrange the chopper was the best friend of Mrs Bishop's most senior adviser, chief of staff and spokesman Damien Jones. Late on Friday Mr Jones said Mrs Bishop would not comment on the referral until the AFP decided whether to investigate.