For his safety, the officer shot the dog and it died.
While the officer was being attacked, two of the five dogs remained in the man's car.
Two of the three dogs which had been released then followed the man, who left the scene on foot, Mr Collins said.
An ambulance was sent to the scene and the officer has been treated for his wounds.
More police staff arrived at the scene and animal control was called.
The offender, who is known to police, is currently being sought by officers.
The man was originally stopped by police following up on reports of a suspicious vehicle in the vicinity.
"When the man failed to comply with the constable, the dogs were set on the officer from the man's vehicle.
"He was placed in a dangerous situation when threatened with the animals," said Mr Collins.
"The officer used his training and tactical options to ensure his own safety and that of the community was preserved."
Police earlier advised four dogs had been set on the officer, but have since clarified how many were involved.
