The Australian Federal Police says it has not found any conduct by former Coalition MP Alex Somlyay related to the employment of his wife that "would constitute a criminal offence".

The AFP assessed allegations revealed by Fairfax Media in January, that Mr Somlyay used taxpayer funds to pay his wife a salary despite her never being seen in the office.

Documents obtained by Fairfax Media indicated Mr Somlyay, an MP for 23 years who retired at the election in September, billed taxpayers $69,157.15 for his wife's employment during 2012-13 alone. But sources close to the former MP's electorate office were not aware of any work completed by Mr Somlyay's wife in or out of the office during the period of her employment.

Mr Somlyay has maintained that his wife worked all of her 2030 hours or 270 days last year from her home office, as a researcher for his speeches and committee hearings.

The AFP press release, issued on Friday, stated: "The assessment of this matter did not identify any conduct by Mr Somlyay that would constitute a criminal offence".

The police also considered reports that Mr Somlyay appeared to have obscured his wife's identity in his list of employed staff. At the top of an internal staffing document, titled ''monthly management report'', the former MP's wife is listed as ''Jennifer Bridget Somlyay''.

But lower on the same page, under a section titled ''electorate employees'', a ''Jennifer Donovan'' is listed. This woman, Ms Donovan, received at least $99,000 for ''electorate office'' work dating as far back as 2003, further documents indicate. Donovan is Mr Somlyay's wife's maiden name.

"The employment of Mrs Somlyay using her maiden name and receipt of payments for work performed was also considered in the assessment," the AFP statement said.

The police statement says that both Mr Somlyay and his wife were interviewed during the investigation, but it is unclear whether any of the former MP's staff were interviewed.

"The AFP considers this matter finalised and will not be providing further comment," the police statement concludes.

Given the AFP has dismissed a criminal investigation, it is now up to the Finance Department to examine the allegations of misuse of taxpayer funds.

Asked, when the story broke, what his wife did to justify her salary, Mr Somlyay told the ABC: "Jenny's a qualified researcher and her work was associated with research for speeches, for committee hearings, for committee work you know, the parliamentary party, and she did that on a regular basis".

But Fairfax Media has been unable to establish what work Mrs Somlyay did during the six months she was employed from June 24, 2013 – the day Mr Somlyay gave his farewell speech to the House of Representatives – to December 9, when her employment ceased.

Mr Somlyay has also declined to explain why his wife received a pay rise the month after he gave his retirement speech. Documents obtained by Fairfax Media show that on July 1, 2013, Ms Donovan's salary increased from $64,085 to $78,844.

It is also unclear why Mrs Somlyay was employed as a researcher for four months after her husband ceased being an MP.

Nor has Mr Somlyay specified what speeches his wife wrote or researched. Hansard reports indicate only seven instances where Mr Somlyay gave a speech on the floor of the House in the period corresponding with his wife's employment. Some of Mr Somlyay's speeches contain only a few paragraphs of text.

Fairfax Media has sought comment from both Mr Somlyay and the Finance Department.

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