A TRAINED boxer charged over the life-threatening injuries of a 23-year-old man has been denied bail in the Perth Magistrates Court.

Connor Pestell, 23, handed himself in to police yesterday afternoon and was charged with assault occasioning bodily harm and grievous bodily harm against two separate men.

The alleged assaults occurred about 3am on March 2 out the front of Ginger nightclub in Northbridge.

A police prosecutor told the court the first victim was talking to a friend of Mr Pestell's when he allegedly became agitated and then punched the man twice in the face.

The second victim, named in court as Mitchell Andrew Cleary, then approached the scuffle and asked Mr Pestell "why did you punch my mate?"

Police will allege Mr Pestell then bounced on the balls of his feet and landed two punches on Mr Cleary's face, knocking him back, with his head hitting the pavement, rendering him unconscious.

Police told the court Mr Cleary's condition is life-threatening, with the injury likely to "cause death or permanent injury".

Police opposed bail because of the extent of Mr Cleary's injuries, because Mr Pestell was friends with some of the witnesses and, if Mr Cleary was to die, the charges would likely be upgraded.

His barrister Henry Sklarz argued bail should be granted because his client handed himself in, had a steady job as a Subway manager and his father - who is the state manager of the sandwich chain - would foot a "substantial surety", and he was also prepared to move back in to the family home in Wembley Downs.

However, the magistrate backed the prosecution and denied bail, remanding Mr Pestell in custody until March 13 for appearance via video link.

Outside of court, Mr Sklarz said it was disappointing Mr Pestell did not get bail and an application might be made to the Supreme Court.

He said the charges could be defended in trial on a claim of self defense.

"At this early stage yes, self defense is one of the considerations," Mr Sklarz said.