Balance-of-power MP Geoff Shaw has apologised for breaching the code of conduct for parliamentarians.

The Frankston MP swaggered into State Parliament on Tuesday after serving an 11-sitting day suspension and told the chamber he was "humbly and sincerely sorry".

"I humbly and sincerely apologise to the house and the people of Victoria for my breach of the code of conduct," he said.

Mr Shaw said the matter had been a distraction and he was "sincerely sorry".

"The buck stops with me and I have taken full responsibility," Mr Shaw said.

Premier Denis Napthine has repeatedly said that the MP's apology would have to be genuine and heartfelt or he would be expelled.

The suspension was part of a government-backed motion that also ordered the MP to repay almost $6838 for misusing his parliamentary vehicle and issue an apology to State Parliament.

The code of conduct breach stemmed from Mr Shaw misusing his taxpayer-funded car to run his hardware business.

Speaker Christine Fyffe said Mr Shaw repaid the money in August and asked that Mr Shaw's explanation be heard in silence.

The long-awaited apology follows a report from Parliament's privileges committee, that found Mr Shaw misused his taxpayer-funded car to run his hardware business.

But the report did not establish that the misuse had been "willful".

Controversy has plagued the Frankston MP's political career, and last September he was charged with misconduct in public office and obtaining financial advantage by deception.

The charges were later dropped.

The independent MP's relationship with the Napthine government has deteriorated rapidly since he was suspended in June.

Senior Liberals have antagonised Mr Shaw by claiming he wanted to get married overseas while on a taxpayer-funded trip and that he had demanded judicial appointments.

Mr Shaw hit back, questioning Premier Napthine's leadership, saying he should consider standing down.

Mr Shaw is refusing to guarantee the Coalition's legislative agenda, and has said he was not briefed properly on legislation.

The controversial MP triggered the demise of Ted Baillieu as premier last March after declaring he had no confidence in him.

Former speaker Ken Smith was also forced to stand down after Mr Shaw accused him of degrading parliament.

Mr Shaw, reading from a statement on Tuesday, said the motion was "tight and prescriptive".

He said a "thorough and rigorous" investigation by the Director of Public Prosecutions into him had found no wrongdoing.

"I always sought a conclusion to this matter and I genuinely apologise if my actions to date did not demonstrate such a commitment,' Mr Shaw said.

He said his goal has always been representing the best interests of Frankston.

"I understand this matter has been a distraction, for which I am sincerely sorry," he said.

with Richard Willingham