Labor's wrongful misuse of taxpayer-funded staff could still be investigated by Victoria Police, the Chief Commissioner Graham Ashton has told a powerful inquiry.

With less than 130 days until the November state election a fresh investigation would be a major distraction for Premier Daniel Andrews and his Labor team and provide plenty of political ammunition to the Coalition.

Earlier this year the ombudsman Deborah Glass found Labor had wrongly used taxpayer funded electorate officers to campaign for votes in 2014.

In response Labor repaid the taxpayer nearly $400,000 and claimed it did not deliberately rort entitlements.

Ms Glass singled out former treasurer John Lenders as the architect of the scheme which she labelled an "artifice".

Graham Ashton confirmed police were looking into the matter. ( AAP: Mal Fairclough )

Following Ms Glass's report, Parliament's privileges committee opened an inquiry and further complaints were lodged with Victoria Police.

Police opened Operation Peach in 2015 over complaints, but that never moved to a full inquiry after initial assessments. Information gathered by police was shared with the ombudsman.

Mr Ashton told the committee on Wednesday that police had been asked to re-open the case following Ms Glass's final report.

Police have been assessing some extra evidence obtained by the ombudsman.

Ms Glass did not recommend, in her report, further police investigation.

Decision on whether to launch formal probe 'imminent'

Mr Ashton said police were still in the assessment stage of Operation Peach, but a decision on whether to open a formal inquiry was "imminent" and would be made in "the coming days".

Mr Ashton shared the ombudsman's view that MP guidelines must be strengthened, saying investigations into MPs in recent years were difficult because of the poor guidelines.

Police also revealed that one former Victorian MP was interviewed as part of Operation Peach.

Labor was found to have wrongly used taxpayers' money during the party's 2014 election campaign. ( AAP: Joe Castro )

Police are assessing whether offences including falsification of documents, misconduct in public office, false accounting, and conspiracy to cheat and defraud were committed, Mr Ashton said.

Earlier Ms Glass told the inquiry that none of the 21 Labor members implicated in the scheme set out to deceive.

"I have no evidence than any of the members set out to deceive," Ms Glass said.

Ms Glass repeated her view that they scheme was "an artifice" and that its architect Mr Lenders, in her words, should have known better.

The ombudsman declined to say how much her investigation had cost, but revealed she had four full-time investigators working on the matter.

Asked if it had cost "hundreds of thousands" of dollars, she replied "certainly not".

The Government spent hundreds of thousands of dollars in its legal fight to stop the ombudsman's investigation.