The Melbourne mother-of-two will spend at least 15 months in prison after pleading guilty to making 14 fraudulent deposits to accounts in her husband's name between December 2014 and July 2016.

The County Court of Victoria was told on Friday that Cook, 44, was in charge of a department dealing with dishonoured and missing cheques, overseeing a team of 162 staff nationally and that her stealing was "entirely for personal lifestyle reasons".

Over 17 months, the mum of two teenage girls used her staff, who trustingly followed her requests without question, to make the fraudulent deposits.

When quizzed about a suspicious transfer of some $4000, Cook was able to bluff her way out. But when pulled up on a subsequent deposit of $29,000, she came clean.

Cook used the stolen $311,529 to buy a jet ski, a car for her husband, to make payments on her investment property, to pay for general household bills and to pay her husband's tax obligations.

This was despite the couple already earning a combined income of more than $450,000 a year.

"You said your family was living a lie they did not have to live," Judge Trevor Wraight said.

"You were in a trusted position as an employee and manager."

Cook earlier pleaded guilty to four counts of obtaining a financial advantage by deception.

She made full admissions during investigations by both police and the bank, becoming "distraught and crying" when questioned.

Two days after she was sacked, Cook repaid the money to ANZ - more than $262,000 once her long-service leave payment was deducted from the overall total.

Judge Wraight said her moral culpability was high, but the fact she repaid the money was of "considerable weight" in determining her sentence.

Cook attempted to avoid jail, arguing her family unit should not be broken up, particularly as her 17-year-old daughter was in her final year of school.

She was sentenced to 24 months' imprisonment, and must serve at least 15 months before being eligible for parole.

Australian Associated Press