Bloody images have renewed calls from Australian doctors to have boxing banned.

Spectators were splattered as Australian boxer Brad Pitt left compatriot Joel Casey dripping in blood during the undercard to the world title fight in Melbourne on Friday night.

A heavily bleeding Casey, aka "2 Gunz," hung on to make the distance for the entire six rounds, despite handing an equally blood-soaked Pitt his 13th consecutive win.

The Victorian branch president of the country's peak medical body, the Australian Medical Association, Dr. Stephen Parnis, said the gory photos showed why the sport should be banned.

"The inescapable fact is that the aim of this sport is to harm your opponent and render them unconscious. There is no safe way of doing that," Parnis said.

"There is mounting evidence that concussion is more serious in terms of life-long implications than we used to think.

"There are also issues of permanent disfigurement, scarring to the face, broken bones and permanent eye injuries. The graphic photos show blood flying everywhere. It's not just revolting, it's a health risk because blood transmits infectious diseases."

But ringside physician Dr. Peter Lewis said Australian boxing led the way in safety, and Casey's ability to defend himself was not affected by the cut between his eyes.

"Not only could the fighter defend himself, he won the last round," Lewis said.

Lewis also said that boxers were regularly tested for transmittable diseases.