Former Victorian Liberal Party state director Damien Mantach who amassed more than $1.5 million by fake invoices told police investigators he always expected to be caught, court documents have revealed.

A transcript of an interview with police on November 18 last year released by the Magistrates Court said he took no steps to "keep this activity covert".

"I always expected that this would be caught at some point," Mantach told police.

On Wednesday, Mantach pleaded guilty to 44 charges relating to dozens of invoices sent to the Victorian Liberal Party from June 2010 until just after the 2014 election, when the party lost government.

He amassed a small fortune through kickbacks from inflated printing and logistics invoices from one of the party's official suppliers, Melbourne Mailing.

He also generated false invoices to get funds through two of his own companies, Campaign Mail Logistics and Parkstreet Online Solutions, for research projects, logistical support and delivery of material that was never supplied.

"Did you receive the money, being $1,558,000 ... as a result of those 53 false invoices?" he was asked by an investigating officer.

"Yes," he responded.

"Did you understand what you were doing was wrong?"

"Yes."

In a transcript of more than 100 pages, details emerged of how he got away with the scams for four-and-a-half years, in particular through Campaign Mail Logistics which he set up in 2010.

"The invoices just started showing up," Mantach said in the interview.

"So there was no control or oversight within the party about that?", he was asked.

'No."

The transcript was a detailed confession by Mantach, who was first interviewed by the Liberal Party's auditors, PPB, in August last year, when he admitted he had committed fraud.

"I came in and gave a full account of ... all the suspect invoices. I gave them everything."

'Common practice' for political parties to pay inflated prices

Mantach would instruct Melbourne Mailing to add a levy to "random" invoices sent to the party, as well as MP offices.

One of the first scams involved an invoice in June 2010 for $16,800 in which 48 electorates were each charged $350 for printing and mailing expenses.

The party paid most of the invoices, but some sent to the offices of politicians were paid for by state or federal authorities.

While the invoices usually came across his desk and he approved their payment, Mantach insisted he did not take the money all for himself.

"Some of the invoicing would actually allow us [the party] to pay for ... other work or activities, so it was all quite legitimate but it was all mixed in."

The transcript revealed it was common practice for parties to pay inflated invoices from printers and other suppliers in order to divert funds to other areas.

"Across all political parties there are close working relationships back with printers, and it would be naive of people to think that that does not allow for a degree of flexibility in terms of the pricing structures that you may have," he said.

"But that's the tip of a much bigger iceberg."

Taking money eased personal pressures: Mantach

Mantach told police that while the CEO of Melbourne Mailing, Felice Armato, did not personally benefit from the arrangement the "Liberal Party's contract would have been his most substantial contract when we were really pumping during the election".

He told police he left the Liberal Party in March 2014 because he was burned out, but also for personal reasons.

"After four years in the role I was burnt out, worn out and I wanted to leave."

The transcript revealed that he initially did it to get himself out of debt.

"For me it was actually never about greed, it was never about ... going off and getting a whole heap of lovely materialistic things," he said.

"I had a number of personal issues that I was not dealing with properly and when I took money it basically relieved pressure in my personal life."

During the interview Mantach talked about how he was trying to modernise the financial processes of the party, like replacing cheque payments with electronic transfers.

It "was one of the broader reforms that I was trying to push through the party at the time. Our finances were archaic up there," he said.

He is due back before the County Court in early May.