The State Revenue Office has been asked to investigate whether Melton MP Don Nardella has paid appropriate taxes on his properties.

State opposition treasury spokesman Michael O’Brien has written to the State Revenue Commissioner Paul Broderick asking him to investigate the former deputy speaker.

The opposition says it wants the office to investigate whether Mr Nardella had been paying land tax on properties in Melton West, Melton, Kurunjang and St Kilda while telling Parliament he had a different primary residence.

Mr Nardella has been under intense scrutiny for claiming $175,000 in second residence allowances designed for regional MPs.

He was ousted from his deputy speaker role and forced to resign from the parliamentary Labor Party for refusing to pay back the money.

A probe by parliamentary auditors PricewaterhouseCoopers found Mr Nardella was paying $200 a fortnight to a family member to live in an Ocean Grove caravan park.

The auditors described Mr Nardella’s living arrangements as “non-prudent, non-arm’s length, potentially non-commercial (low “rent”), and arguably opportunistic, designed to ensure continued enjoyment of the second residence allowance”.

“The member already had a second residence in Melbourne so that, at the time, a simpler option might have been to relocate to the second residence in Melbourne or his Melton constituency,” the auditor’s report stated.

In his letter to the State Revenue Commissioner, Mr O’Brien said it was important “for the integrity of Victoria’s taxation system” that only “properly founded exemptions” for land tax were claimed.

“In the event that the Member for Melton claimed any of the properties that he owned as his principal place of residence to the SRO for the purpose of claiming a land tax exemption, this would appear to contradict the findings of the PwC report, which found that Mr Nardella’s [principal place of residence] were not owned by him,” Mr O’Brien said in his letter.

There have been calls for Mr Nardella to be investigated by Victoria Police, the Australian Electoral Commission and the Victorian Electoral Commission.