A WESTPAC bank manager who stole almost $3.7 million from the Belmont branch over 20 months to fund his out of control gambling addiction has been jailed for more than five years.

Daniel Petkov, 37, falsified bank records and stole up to $400,000 in cash at a time from the bank between July 2016 and February 2018.

Petkov, who had undiagnosed bipolar disorder, was spending up to 16 hours a day at slot machines and gambled away all of the stolen money.

District Court Judge John Prior jailed Petkov for 5½ years today for one count of stealing as a servant.

He said the stealing was persistent and involved a significant breach of trust from an employee in a senior position.

Judge Prior accepted Petkov had an undiagnosed mental illness at the time and said one of the manifestations of the illness appeared to be a gambling disorder.

“It was not self-induced,” he said.

Petkov has since sought treatment for bipolar disorder and is now considered to be in remission.

The court was told Petkov stated gambling at age 21 and had once been granted high roller status at Crown Melbourne.

Petkov was caught in February when a full branch cash count was done after his manager noticed an automatic teller machine balance was unusually high.

His colleagues had unwittingly been involved in hiding the theft and were interviewed about the dodgy transactions after he was charged.

Petkov had worked for Westpac for about 10 years and had worked his way up from being a bank teller to a manager.

Defence lawyer Tom Percy said Petkov’s days of dealing with money were over.

“He will never be in the financial industry again, on any level,” he said.

“Today is a life changing day for him in many respects.”

Prosecutor Gabrielle Clarke described Petkov’s behaviour as “deceitful to the extreme” and said his crime had cast a shadow over all of the staff at the branch.

“Members of the public need to know that they can trust their bank because this these type of offences strike at the very heart of the financial system,” she said.

Petkov has been ordered to pay back the $3,674,495 he took from Westpac.

The court was told he had previously offered to pay back $50 a week but that offer had been knocked back by the bank.

Petkov will be eligible for parole in 3 ½ years.