A woman was allegedly assaulted at a roundabout in Bonner late on Thursday night.

Police say the alleged assault occurred at the roundabout of Roy Marika and Essie Coffey streets at around 10.45pm.

A person, who is believed to either be a nearby resident or was close by at the time, interrupted the altercation.

Police want to speak to this person and with anyone else who may have witnessed or heard the altercation.

Call 1800 333000 or via the Crime Stoppers ACT website.