The victim was in the care of Women's Refuge, and the offender was expected to appear in Dunedin District Court today.
Early yesterday morning a 25-year-old man was knocked unconscious during an alleged assault near the entrance to Dunedin Hospital.
Police and hospital security staff assisted the victim who suffered head and scalp lacerations near the Gt King St entrance shortly after 2am.
Two alleged offenders were apprehended a short time later on George St, Acting Snr Sgt Chris George said.
Police were yet to speak to the victim, who was discharged yesterday, about the incident.
One of the men was expected to appear in Dunedin District Court today charged with injuring with intent.
Extra police staff had been rostered on this weekend due to the festive season, and while Friday night was quiet, the "steady stream of assaults on Saturday night was disappointing".
"It is unfortunate that these assaults have occurred. I guess the good news is people have been locked up, but it would have been better if they didn't happen in the first place."