A security guard was bashed with his own torch after he disturbed a group of burglars at the Thames racecourse overnight.
One man has been arrested and police have told the others to hand themselves in before they are tracked down.
The 49-year-old victim was carrying out a routine patrol when he disturbed what was thought to be a group of five burglars, said Detective Sergeant Martyn Hughes.
Four of the group fled but the guard grabbed the fifth person and a struggled developed, during which the offender grabbed the guard's metal torch and hit him several times around the head and body.
Through out the attack, the security guard refused to let go of his attacker, who then gouged him in eye, forcing him to release his grip.
The man fled but left behind a hooded sweatshirt.
A 22-year-old man was later found hiding in a tree and arrested.He was not thought to be responsible for the assault.
The guard was taken to Waikato Hospital by ambulance where he was treated for eye injuries.
"I would like to say to the offenders involved that there has already been quite serious consequences from what occurred and it would be better for you to give yourselves up as opposed to police having to track you down," Mr Hughes said.
Police believed the person responsible for the victim's injuries would be sporting possible bruising to his face because the guard put up a fight, and they asked any medical centres who have treated someone for possible black eyes or facial bruising to contact them.
"Likewise, we would like to hear from anyone who knows someone suffering from unexplained bruises or scratches to the face to contact Thames police".