Michael Glennon, 69, is believed to have died of natural causes in an Ararat jail, where he was serving a minimum 10 and a half year sentence for child sex offences.

Corrections Victoria spokesman Mario Xuereb confirmed that a 69-year-old man died overnight at Hopkins Correctional Centre in Ararat, 200 kilometres west of Melbourne.

In 2003 Glennon was sentenced to at least 15 years' jail, reduced on appeal, for 23 child sex charges against three victims. It was the fifth time since 1978 that the Catholic priest had been convicted for abusing children, the youngest aged seven. Some offences were committed while on bail.