The Finance Department has claimed it is "not possible to determine" whether Tony Abbott's travel to the wedding of then parliamentary colleague Sophie Mirabella was correctly charged to the taxpayer as "official business".

Emails released under freedom of information laws reveal conversations between the Finance Department and the Department of the Prime Minister and Cabinet concerning Mr Abbott's travel to Ms Mirabella's 2006 wedding at Wangaratta.

Mr Abbott charged taxpayers $1090 for the wedding trip, but repaid the amount late last year after Fairfax Media ran a series of stories about senior MPs charging taxpayers for questionable travel.

Despite the Prime Minister making the personal decision to repay the money, the emails suggest Mr Abbott could not rely on the Finance Department to provide guidance.

Most revealing was an email, dated October 5, 2013, sent from the Department of Finance to the Department of Prime Minister and Cabinet.

"Mr Abbott's claim for the June 2006 travel to Albury was claimed as official business as a minister," the email states.

"Finance has become aware that the travel coincided with the wedding of a parliamentary colleague – Ms Sophie Mirabella."

The email goes on to say that Finance does not have "access to the paperwork today ... as it is held in archive".

"On the basis of the information available it is not possible to determine whether the travel was made in accordance with the relevant determination," the email concludes.

The FOI request was submitted by citizen journalist Margo Kingston, who said she ''crowdfunded'' the payments for the request.

The failure of the department in charge of MP entitlements to provide a ruling follows a pattern in which it has been unwilling to comment or take action on any of the examples of questionable travel claims revealed by Fairfax Media.