A female police officer who received a mild concussion during a violent struggle outside a Central Otago hotel overnight will be off work for "a couple of days" while she recovers.

The officer and a fellow constable were conducting a hotel visit in Alexandra when they were told a police patrol car had been damaged about 11.20pm yesterday, Inspector Mike Cook said.

They went into another hotel looking for the person believed to be responsible for the damage.

While taking the man outside, "he basically attacked them," Mr Cook said.

The officers pepper sprayed the man but it was ineffective and the fight ended up on the ground.

"Assistance from members of the public present enabled the suspect to be restrained until additional police staff arrived."

The female officer suffered a "substantial blow" to the head, while the male officer was hit in the jaw and bitten on the arm.

Both were treated at the police station.

Mr Cook said the female officer will not be back at work for a few days after she received a mild concussion.

"I'm guessing this morning, she is going to have quite bad bruising on her face."

A 21-year-old Alexandra man is due to appear in Dunedin District Court today charged with injuring with intent, aggravated assault on police, assaulting a person assisting police, criminal damage and resisting arrest.

- NZPA