A CONVICTED wife beater who also assaulted his 24-year-old daughter has been reinstated to his job as a prison guard despite repeated attempts by Corrective Services to sack him.

The Industrial Relations Commission found there was no connection between Michael Silling's ability to carry out his duties at Goulburn jail and his ''out-of-hours criminal history'', ordering he be returned to work.

Justice Wayne Haylen said the sacking of Mr Silling after his third conviction for domestic violence was ''harsh, unjust and unreasonable''.

Mr Silling was fired in June 2011 after 15 ''unblemished'' years as a correctional officer at the high-security Goulburn jail, home to killers including Ivan Milat.

According to the commission's finding late last month, he was convicted in February 2011 of assaulting his wife during an argument at their home and, after pleading guilty, was handed a nine-month good behaviour bond and ordered to undergo anger management counselling and take prescribed medication.