The Digger, a veteran of the Korean and Vietnam Wars, then discovered the 13 service medals had been stolen from his bedroom, along with some jewellery.
"I can think of nothing worse to occur in the lead-up to Anzac Day than the theft of these medals," Mr O'Farrell told reporters in Sydney.
"It was a mongrel act and if the mongrel who did it wants to redeem him or herself, return those medals anonymously to a police station so they can be restored before [today]."
Cabramatta local area commander Superintendent Wayne Murray said the Digger was "absolutely devastated" at the loss.
"The monetary, street value of these medals is not that much, but they're of great sentimental value to him," he said yesterday.
"This is cruel. To have your home broken into at any point of the year is obviously distressing, but to have your home broken into and medals stolen and just before Anzac Day is a low act.
"I would describe the [thief] as a knuckle-head."
Police are continuing investigations, including checking local pawn shops, after having found leads following a forensic examination of the home.
- AAP