During the incident, Harvey came up behind an officer and attacked him with a tomahawk.
Harvey then ran off, hiding the tomahawk in shrubs, while his victim lay unconscious on the ground.
"He then climbed on to the roof of a nearby kindergarten where he watched police arrive, tend to their colleague and search for him [Harvey]," the summary said.
Harvey stayed on the roof for several hours and wasn't found until the next evening at his home.
The injured constable was rushed to Rotorua Hospital before being transferred to Waikato Hospital with a skull fracture and bruising to the brain.
During surgery his head fractures were repaired with plates and screws.
The officer is still off work with effects of his injuries including headaches, tiring easily, mood changes, and difficulty with memory.
Harvey's lawyer, Martin Hine, reserved his submissions until sentencing.