Police have charged a man over a sexual assault on a young mother in North Melbourne five years ago.

Detectives from the Sexual Crimes Squad arrested a man on Wednesday as part of their investigation into an alleged sexual assault in North Melbourne in the early hours of June 30, 2013.

He has been charged with one count of rape and one count of intentionally cause serious injury and will appear at the Melbourne Magistrates Court on Wednesday evening.

Earlier this month, a $500,000 reward was announced for information in relation to the incident.

No one had been charged over the sexual assault, despite a public call for information at the time, but police revealed weeks ago that they were close to making an arrest.