A man labelled the architect of Victorian Labor's $388,000 rorts-for-votes scheme has defended the operation, saying he thought it was fine because parliament kept paying the bills.

Former treasurer John Lenders on Thursday would not elaborate on documents that said Premier Daniel Andrews had a casual electorate officer working for him while opposition leader in 2014.

Mr Lenders is being grilled by parliament’s powerful privileges committee after a damning Ombudsman report in March found Labor systematically misused $388,000 in parliamentary allowances to partially fund its winning 2014 election campaign.

The scheme saw public-paid electorate staff directed to promote party candidates.

Mr Lenders questioned the inquiry’s legitimacy, declaring he had not received “procedural fairness” and rejected the Ombudsman’s suggestion the scheme was an artifice.

“I believed I was working within an acceptable framework,” Mr Lenders said.

“It was a fraught option in a highly-charged environment of an election.”

Mr Lenders said he had “workshopped” expanding Labor’s long-established staff pooling arrangements with Department of Parliamentary Services secretary, Peter Lochert.

He worked out a way to increase staffing by using the communications budget.

“When I went to parliamentary services I wasn’t going to tell them exactly what they (the staff) were going to do,” Mr Lenders said.

“You’ve got to try it on and if (parliamentary services) pay, you know it’s met their ultimate test.”

Mr Lenders believed the scheme was legitimate when it started in late 2013 but acknowledged it became “grey” when field officers who doubled as electorate officers started “proselytising” closer to the election.

“I should have paid more attention,” Mr Lenders said.

Mr Lenders made a statutory declaration to the Ombudsman that mentioned a casual electorate officer was working at Mr Andrews’ Mulgrave office.

The former treasurer said he didn’t know who paid for that officer and that he had nothing further to add to his declaration.

Sitting upper house MPs Nazih Elasmar, Adem Somyurek and Jenny Mikakos are also expected to give evidence on Thursday.

Victoria Police Chief Commissioner Graham Ashton has already revealed the force was again looking at whether to launch a criminal investigation into the scandal.

Ombudsman Deborah Glass told the committee decades-old staff pooling arrangements by Victorian Labor made it confusing and difficult to investigate and MPs who signed up seemed to genuinely believe they were acting within the rules.

By Kaitlyn Offer