That officer was hospitalised with a serious concussion.
Edwards said his staff member was also taken to hospital after the alleged assault at the AC Baths last Wednesday.
Officers were called to the complex after concerns were raised by staff about alleged threatening behaviour by a man visiting the baths.
"Two officers attended and attempted to take the man into custody for an outstanding warrant for his arrest.
During this process, one of the officers was left unconscious after being allegedly assaulted by the man.
The officer's safety alarm was activated and the other officer was also able to call for assistance."
More officers were sent to the scene and a man was arrested.
He now faced two charges of assaulting police and one of injuring with reckless disregard.
He is set to reappear in court next week.
Edwards said the injured officer was now "recovering well at home".
"We continue to provide our injured colleague with support and we're grateful they did not receive more serious injuries."
Police Association president Chris Cahill said there was an increase in serious violence towards police that was alarming.
"Certainly the knock-out punches starting to become increasingly concerning.
"We had another officer last weekend in Auckland who was king-hit from behind and knocked completely out, unconscious as well.
Cahill said it had become noticeable that officers were suffering more serious injuries when they get attacked and he put that down to an increase in popularity in fighting sports.
"I think one of the issues that I'm a bit worried about with these assaults on police is that there's a lot of young guys now doing the UFC and Mixed Martial Arts training.
"It's a very popular sport, so they're not just people who want to fight but they're actually people who are trained and I think the risks are increasing because of that.
"These assaults have much more serious outcomes, especially if you're king-hit without any warning. The risk is very high and you can suffer a serious injury."
