An 81-year-old retired Australian Catholic priest has been fined A$1000 (£664) by a Perth court for biting off a fellow clergyman's ear during a row over a parking spot.

Fr Thomas Byrne pleaded guilty to assault and injury to his neighbour Fr Thomas Smith, 81, also a retired clergyman.

Perth magistrates spared Byrne from a criminal conviction, after his lawyer Seamus Rafferty presented a psychiatric report maintaining that the former priest suffered from frontal lobe dementia.

Byrne's condition caused changes in his character and social interaction and clouded his ability to judge, Rafferty said.

Byrne attacked Smith during a confrontation over a parking space at a retirement home in the Perth suburb of Dianella in November.

After they calmed down, Byrne reportedly pointed to something Smith had dropped during the brief scuffle. Smith picked it up and put it in his pocket without looking at it.

That something turned out to be a part of Smith's ear, the court heard, but he did not realise that until he got back to his room and took the object out of his pocket.

Rafferty said Byrne's act was out of the character for the priest who had been dedicated to his community for his whole life.

"He is deeply ashamed at his behaviour,'' Rafferty said.

Smith did not suffer long-term damage from the incident.