A Roman Catholic priest who unleashed a torrent of expletives and racist abuse against skateboarders outside his Australian cathedral, only to have the outburst filmed and placed on YouTube, has been put on leave.

"Move, you f****** fool," Baron tells one skater in the video, slapping one of the group across the head and prompting a torrent of abuse in reply.

Pointing to a skater lying on the ground, Baron is heard telling the youth "Little foreigner there, look at the sleepy eyes, black hair."

"At least he's got hair. You f****** bald p****," one youth replies. Others spat on and shoved the furious priest.

The embarrassed Catholic Archbishop of Melbourne, Denis Hart, placed Baron on indefinite leave after the outburst appeared on YouTube, while security guards began patrolling the cathedral grounds Wednesday amid threats of reprisal attacks.

"I want to relieve the dean of the pressures and responsibilities he carries as dean of the cathedral," Hart said, promising further action.