The Victorian Liberal Party's former state director, Damien Mantach, ripped off taxpayers as well as his own party via an elaborate scheme that ran for four and a half years, court documents have revealed.

Mantach, 42, has pleaded guilty to a total of 44 charges relating to false printing of invoices and other fraudulent expenses billed to the Liberal Party of Victoria, as well as others that were billed to MPs' offices that were then paid by state and federal authorities.

Mantach used the money to buy shares, a car, invest in a cafe and to make loan repayments on his home at Ocean Grove.

"Initially .. I was under substantial financial duress and I had just gotten myself into too much debt," Mantach told police in an interview, which was detailed in the summary of offences.

"Their searches have gone looking for racehorses, they've gone looking for the offshore accounts, they've gone looking for the big boats ... the Ferrari in the driveway... there was none of that. It was not about that for me.

"When I took money it basically relieved pressure in my personal life."

Mailing company thought scheme 'was legitimate'

The document revealed the intricacies of Mantach's operation.

Inflated printing invoices would be sent by the party's official printer, Melbourne Mailing, which would take its legitimate share and send the extra money - dubbed a 'levy' - to Mantach.

That happened via bogus invoices from Campaign Mail Logistics, a company which was started by Mantach and his wife Jodie, in May 2010.

The business was linked to a bank account, also in Jodie Mantach's name.

Mantach provided Melbourne Mailing with an ABN number from a legitimate Liberal Party entity, not Campaign Mail Logistics.

As a result, when its chief executive Felice Armato performed checks, he thought it was a legitimate arrangement.

"Armato believed the accused needed to arrange to pay a company that was performing services for the Liberal Party, but [the] party could not be seen to be paying for these services directly," court documents said.

"He did not suspect anything untoward, and given the accused's senior role within the Liberal Party, assumed he had full authority to give these instructions.

"The accused indicated it was all 'above board' and that Melbourne Mailing would not be 'out of pocket'."

Mantach used wife's bank account to redeem claims: documents

Mantach also established a firm called Parkstreet Online Solutions, which purported to offer IT and social media services to the party.

It was used to bring in payments totalling $256,000 between June 2013 and October 2014.

The false expense claims began in June 2010 and continued until December 2014.

During that time he lodged 53 fake expense claims, which were reimbursed through Jodie Mantach's bank account.

There is no suggestion she was aware of the scam.

More than 10 invoices were lodged in December 2014 alone, in the weeks after the Liberals lost government in the Victorian state election.

"The invoices contained details of work purportedly performed, which were not," the document stated.

Inflated invoices sometimes carried the names of state and federal MPs, which were then paid out of parliamentary mail allowances.

It was not clear from the document how much taxpayers had paid in the scam or which MPs were used in the ruse.

Liberal staffer told by Matach 'not to worry'

The documents showed in the "latter stages of this offending" a Liberal Party staffer, Andrew Camenzuli, questioned the levy.

But Mantach told him "don't be concerned about that. I'll take care of that".

The party discovered the missing money during an audit in August 2015.

Mantach "fully disclosed what he had done and provided copies of the false invoices and his bank statements," the document said.

"He extended his full cooperation."

Later, auditors tracked Mantach's spending and found he had bought $500,000 in shares, a cafe for $611,000 as well as an $81,000 car and home loan payments worth $45,000.

They recovered $466,713 from Mantach.

Mantach moved to Victoria in 2008 after serving as state director with the Tasmanian Liberal Party from 2005.

He was the party's state director from 2011 until his resignation in March last year.

He is due to return to court in early May.