Police allege the 38-year-old man punched the victim, 23, from behind, making contact with the side of his head.

The victim was taken to Wagga Base Hospital for treatment.

Acting Inspector Steve Magnone said the incident began when security guards scanned the accused's false identification at Que Bar on Baylis Street, identifying the man as a person barred from the venue.

"The accused was requested to leave, which he began to do, but another unknown male was reported as being argumentative with the security guard leading to the accused returning and throwing the punch," he said.

The man was arrested Monday afternoon by police and granted strict conditional bail.