The ACT Supreme Court heard the man also posed as a technician to gain access to the machines and used the money to fuel a gambling addiction, losing thousands of dollars at casinos.

His crimes were described as sophisticated and ''like a computer game''. But the court also heard he suffered from psychological disorders so serious he was banned from accessing his inheritance without his parents' permission.

The man, who cannot be named, had pleaded guilty to multiple charges of theft and unauthorised modification of data and was sentenced recently, with the sentencing remarks published last week.

Chief Justice Terence Higgins said the man used considerable deception to carry out several series of offences starting in March last year when he accessed ATMs around Canberra and effectively reprogrammed the machines. As a result, he was able to force the machines to dispense more money than he had in his bank account.

The court heard the man had been frank with police when he was caught, telling them exactly how he broke into the ATM software, and had effectively helped forestall any similar crimes in the future.

He was granted bail but was picked up again last October after posing as an ATM technician to steal thousands of dollars from cash machines at the Westfield Belconnen shopping centre.

He had called the company responsible for the machines and pretended to be a technician to obtain access codes which allowed him to reprogram the machines and take the money.

He was arrested at a convenience store in Civic after ringing the company and asking for codes to fix an ATM at the store.

At the time of the offences the man was the subject of a good-behaviour order imposed for ''quite different matters''.

When he was arrested again in October he was also on strict bail conditions, which included a curfew and a ban on entering casinos.

Chief Justice Higgins accepted that the man had been suffering a gambling addiction and had psychological disorders that required medication.

But the man had suffered side effects from the drugs and had stopped taking them, which had triggered a more intense desire for gambling.

He said the man's disorders were so serious that he was not allowed to access his inheritance without permission from his parents, who were trustees of the account.

Chief Justice Higgins said the man's crimes were like a computer game because there was no personal confrontation between him and any other person.

''Against that, while it might be said that there was no individual victim at risk, and no individual who was personally defrauded, he did place a very valuable banking system at risk and that is not insignificant,'' he said.

He said the man had showed remorse for his actions and had offered to pay back the stolen money.

Chief Justice Higgins sentenced the man to a total of 29 months' jail, backdated to account for time already served.

The man will serve six months of the sentence in weekend detention and the remainder was suspended with a two-year good-behaviour order.

He must also repay $29,270 within two years.