A Lyneham man who pleaded guilty to hacking into two ATMs to steal $10,400 was already on bail for stealing thousands more dollars from cash machines to feed a gambling addiction, a court has heard.

Luke Angus McLaren, 23, posed as a technician when he hacked into the machines at the Westfield Belconnen shopping mall last Friday, collecting $6400 from one machine and $4000 from another.

According to the statement of facts tendered in the ACT Magistrates Court, McLaren then went out and blew the money during a 30-hour gambling spree at Canberra Casino at the weekend, losing a total of $52,000.

When he ran out of money and had to leave the casino about 4am on Sunday, he tried to hack into another ATM to steal more cash but failed because the machine had been secured by the company which owned it.

McLaren then called the ATM company several times, pretending to be a technician who needed access to the cash machines.

Police caught him red-handed during one of the phone calls after he told the company he was at the Quick 'n' Go convenience store on Alinga Street and needed a technician's code to fix an ATM at the store.

In a police interview, he admitted the thefts and told officers he had gambled the money away online, at Canberra Casino and the Queanbeyan Leagues Club.

Yesterday McLaren was charged with two counts of unauthorised modification of data and two counts of theft.

He has already pleaded guilty to another 29 charges related to ATM hacking and passing bad cheques.

But he has pleaded not guilty to multiple counts of fraud.

Police say McLaren hacked into the operating software of the ATMs and triggered an error which allowed him to withdraw more money than he had in his account.

Defence lawyer Andrew Fraser said his client had been offered a chance to live with his parents at the family home in the central-western NSW town of Cowra and there were people who would look out for him in the community.

He said McLaren had a full-time job available in Cowra for the next few months and a mental health report showed the man was less likely to re-offend if he was working.

Mr Fraser said McLaren had no history of failing to appear at court and would be supported by his family.

But prosecutor Anthony Williamson argued McLaren had breached most of his bail conditions by committing further thefts, breaking a court-imposed curfew and entering a casino.

Magistrate Peter Dingwall refused bail and remanded the man in custody until December.