An ANZ employee in country Western Australia who withdrew $56,596 from a pensioner's account has been jailed for two years.

Mary Mercedes Lea'aetoa was sentenced by Judge Belinda Lonsdale in the Albany District Court on Thursday. 

The court heard Lea'aetoa, who pleaded guilty to fraud charges last year, made multiple withdrawals from a 63-year-old woman's account over nine months.

The 26-year-old accomplished the theft by filling out forged withdrawal vouchers.

Her victim did not notice the unauthorised transactions at first but tried to seek help from ANZ when she found larger sums from $600 to $5,000 being frequently withdrawn. 

The pensioner, who is known to Lea'aetoa, is in palliative care. 

Prosecutors told the court the former teller used the stolen cash to buy a new iPhone, arguing her offending was "greed as opposed to need". 

But defence lawyer Sonia Anderson rejected that claim and told the court her then-23-year-old client was expected to financially support her family by buying food and alcohol for them. 

Ms Anderson said her client felt "ashamed" of the crimes and her family had rejected her since her arrest. 

ANZ dismissed Lea'aetoa following an internal investigation which ended in a four-and-a-half-hour interview, but she denied her employer's accusations during the meeting. 

The company concluded on the balance of probabilities Lea'aetoa was likely guilty and reported the matter to police. 

Judge slams 'despicable' conduct

In sentencing, Judge Lonsdale said she had noted the former bank employee also refused to answer questions during her first police interview. 

However the judge did outline there was evidence Lea'aetoa stole money due to being "financially controlled" by her family, who took her salary and left her with $50 each week. 

Judge Lonsdale said a defence submission for a suspended sentence was "not appropriate" and the "repeated nature, continual breach of trust and amount of money stolen" warranted an immediate term of imprisonment. 

A spokesperson for ANZ said a refund was issued to the victim and the institution took its responsibilities to customers seriously. 

Lea'aetoa will be eligible for parole in July 2025.