Barnaby Joyce and his partner Vikki Campion's taxpayer-funded travel has been subjected to scores of inquiries by an independent watchdog set up to stop federal politicians misusing their entitlements.
The Independent Parliamentary Expenses Authority (IPEA) began an inquiry into the pair in February — and four months on, it is still not finished.
The watchdog told the ABC it had asked Mr Joyce and Ms Campion "many questions" about their expenses.
"The IPEA has asked many questions of Mr Joyce and third parties for the purpose of conducting this audit," a spokeswoman said.
"Mr Joyce has responded to 79 questions from the IPEA in relation to his travel expenses to date."
The IPEA revealed it had asked Ms Campion "approximately 57 questions", but did not specify by deadline whether she had responded to them.
The couple, whose son Sebastian was born in April, has expressed frustration with the investigation and have strongly rejected any suggestion they misused taxpayer funds.
During their controversial paid television interview with the Seven Network, Mr Joyce claimed the IPEA had "investigated this to death".
"I've had like 160 inquiries, and at this point, not one, not one has come up with saying, 'Oh this is a problem'," the former Nationals leader said.
In a move likely to frustrate Mr Joyce, the IPEA indicated its inquiry was continuing.
"Further questions may be asked as the audit progresses," the IPEA's spokeswoman said.
"As the audit has not yet been finalised, we are unable to comment on the findings."
Mr Joyce is under pressure from some Nationals to reconsider his political future.
They argue he is a distraction for the Federal Government.
He is also the subject of a sexual harassment complaint, which is being handled by the New South Wales Nationals.
Mr Joyce has made it clear he wants that matter "finalised ASAP".
