Chief Justice Terence Higgins has ordered fraudster Timothy Patrick Cousins to serve a non-parole period of four years, two years of which will be served as weekend jail.

Over the space of seven years, Cousins defrauded $1.19 million from his long-time employers, the Catholic Education Office of the Archdiocese of Canberra and Goulburn.

The senior payroll officer used his high level access to create fictional employees, reopen the accounts of former employees and, on some occasions, disguise his transactions as stipends paid to nuns and priests.

Detectives, eventually tipped off by an anonymous letter, managed to track the 51-year-old swindler's digital paper trail all the way to bank accounts in Thailand. Some of the money was apparently used to buy land and build a house in Thailand.

Police say Cousins confided in his daughters after he was found out, describing the fraud as being ''like gambling'' and saying he could not stop.

Cousins' undoing was an anonymous letter, slipped into a yellow envelope and then delivered to the office's Manuka headquarters in October 2010.

The document alleged the payroll officer had been embezzling money for at least a decade, by making additional fortnightly payments to himself.

It raised the suspicions of his bosses and police were called in, prompting months of investigation into financial irregularities at the office.

Cousins initially pleaded guilty to 153 charges in the ACT Magistrates Court, and was committed to the ACT Supreme Court for sentence.

The office of the Director of Public Prosecutions yesterday offered 10 charges as representative counts encapsulating the entirety of the man's criminal conduct.

Cousins maintained his pleas this morning to charges of theft of a chose in action, dishonestly obtaining stolen property and unauthorised modification of data.

The court heard the defendant was a man of previous good character, with no significant criminal history.

But the judge noted that was often the case when dealing with white-collar criminals, and said the man had been able to pull off the fraud "by reason of the position of trust that he held and of course by his apparent trustworthy character and nature".

Chief Justice Higgins took into account the man's pleas of guilty and clean record, but said there was a need to send a message of denunciation.

Cousins will be eligible for release from full-time custody in March 2014, but will then have to spend his weekends behind bars for two years.

In a statement issued this afternoon, deputy director Mark Hogan said the Catholic Education Office had "reorganised its payroll section and strengthened its internal control procedures" in the aftermath of the fraud.

"Staff and school community members have done a great deal to put this matter behind them and to move forward in an environment characterised by ethical, honest and transparent behaviour," he said.

"The judgment of the ACT Supreme Court has brought some relief and closure for the Catholic Education Office and all concerned with Catholic education in the Archdiocesan school system."