Police prosecutor Sergeant Beau Riley spoke out against Thomas Charles McKellar, 25, of Amaroo Crescent, for assaulting the on-duty senior constable.

Solicitor Katarina Duncan said the police officer "got in a nice right hook and other punches," indicating McKellar was already punished before being sentenced.

However, Sergeant Riley said McKellar had "well and truly" crossed the custodial threshold and the senior constable has faced personal consequences as a result of being spat on.

"[The officer] has just had a brand new baby girl," he said.

Sergeant Riley said the police officer had to be tested for a range of diseases such as hepatitis B as a result of being spat on.

He said the officer has to have limited contact with his baby while he waits for the results of the tests.

"It far [outweighs] anything that happened to Mr McKellar," Sergeant Riley said.

According to police, McKellar was in custody at Orange Police Station and was refused bail at Orange Local Court about 1.50pm on February 12.

He was to be transported to corrective services but started hitting and kicking the dock door and acting in an aggressive manner towards police.

The police officer opened the door to the dock and McKellar stepped onto a seat.

The senior constable then took hold of McKellar's hands to handcuff him and he and another officer led him from the dock towards a police vehicle.

However, McKellar turned his head and spat on the Senior Constable's cheek and ear.

When the police officer turned to face McKellar he believed he was about to spit again so to stop him he used "approved defence techniques", as mentioned by Ms Duncan, and took McKellar to the ground.

In the process of taking McKellar to the ground, the officer's glasses, valued at $550 and watch valued at $500 were damaged beyond repair.

Magistrate David Day said the offence was so "disgusting" that he did not consider a community-based sentence to be appropriate.

"There needs to be appropriate punishment, there needs to be general deterrence," Mr Day said.

He ordered McKellar to pay $1050 in compensation to the senior constable for damaging his watch and glasses. Mr Day also gave McKellar a 12-month jail sentence with a six-month non-parole period for the assault.

The sentence will date from February 14, 2022 until February 13, 2023, and his non-parole period will continue until August 3. He is also in jail on other matters.