Police say the bullet was fired into the ground and no one was injured.
However, protocol requires the homicide unit to be called in to assist with an administrative review conducted by the Professional Standards Section.
During the review, the weapon will also be thoroughly examined.
The officer involved, who has five years experience, was stationed outside a house where officers had been called to a report of an assault in progress.
Police believed at the time there might be firearms in the residence.
In total, nine people who were coming and going from the home were taken into custody. Three were wanted on outstanding warrants and breaches, and another faces charges after drugs were found in her possession.