Izett admitted a Crimes Act assault on the officer and was remanded in custody for sentence on September 26.
A second offender, unemployed Dunedin man Daniel James Stronach, spat blood and saliva on a police officer's face at the Dunedin Central Police Station on August 2, Sgt George said.
Stronach had been smashing his head against the metal doors, causing cuts to his head.
He also ran the length of the cell and crashed head first into the metal doors.
A constable stood in front of the doors and spoke to him, trying to calm him, but Stronach spat saliva and blood through the door and on to the officer's face.
While going through the arrest process, the defendant said he was hepatitis C positive.
The constable who was spat on and two other constables who arrested and physically restrained Stronach were not injured, but all three had blood tests to determine whether they had contracted hepatitis, Sgt George said. They were still awaiting the results.
Stronach admitted assaulting the three officers and resisting one of them, his explanation for his behaviour being he was "coming off K2".
Judge Michael Crosbie remanded him in custody for sentence on October 18 when he is also to be dealt with on other charges.
Two of the officers had gone to Stronach's home about 3.30pm on August 21 to investigate an assault complaint. The defendant tried to assault one officer with a skateboard and was arrested and handcuffed but actively resisted.
After being placed in a police car, he hit his head violently against the window several times. He kicked at the first constable, who was holding him to try to stop him harming himself. At least two of the kicks made contact with the officer's head, Sgt George said.
During the drive to the police station, Stronach continued struggling and kicking at the first officer. He also managed to kick the second constable, who was driving, in the back of the head.
Stronach was restrained again and was placed in a holding cell at the police station where the spitting incident occurred.