A man is in custody after breaking a police officer's nose in Whanganui early on Sunday.
The officer was arresting a man who had been fighting, when he was punched in the face by another man.
The officer also had concussion and has had hospital treatment.
The area commander for Whanganui police, Inspector Duncan MacLeod, says the officer is now waiting to find out if he will need to have surgery to correct the damage to his nose.
A man will appear at the Whanganui District Court on Monday charged with aggravated assault.