It was a kindergarten safety lesson ... but it went wrong when Tyler Hatton tried to pat the star

A 3-year-old boy was bitten by a police dog in front of more than 30 children during a kindergarten visit that was meant to teach the children about dog safety.

Napier toddler Tyler Hatton received puncture wounds to his lip and a gash to the bridge of his nose in the incident, at Riversdale Kindergarten.

"It's a regular programme where they go in and take a dog in," Tyler's father, Matthew, said last night.

"It's about dog safety, ironically. I wasn't there but apparently he was patting the dog - they weren't crowding it or anything - and the dog just spun around and gave him a nip on his face."

Mr Hatton said Tyler was recovering well at home, but was a bit grumpier than usual and "not quite himself".

Police eastern district operations manager Inspector Mike O'Leary and the dog handler visited the family to apologise and meet Tyler.

Mr Hatton said the family were not angry. "These things happen.

"The dog handler, he's horrified. He's mortified that it happened with his dog. It's the first time it's happened so he's quite freaked out. He's upset that it's happened.

"The police have been great ... They're going to investigate it and look at the dog, do some retraining with the dog and go from there. They're very thorough."

Mr Hatton said the family had faith the police investigation would resolve what happened and prevent it occurring again.

"I'm sure they will get to the bottom of it. These guys do this for a living, they've been training police dogs for ages."

Mr O'Leary said police were investigating the incident, and the dog's health, physical condition and behavioural status were being reassessed by a senior dog handler.

The dog lived with his handler and his young family and had never given any cause for alarm.

It was "highly unusual" for a police dog to react badly to a small child," Mr O'Leary told stuff.co.nz.

"We are working with the handler and trying to ascertain why the dog may have acted the way it did.

"The handler is devastated that his dog could have done this to a small child, and is very upset by the incident."

Mr Hatton said he did not want to see the dog destroyed.

"We would rather they didn't ... These dogs cost a lot to train and sometimes these things happen.

"I'm sure they can fix the problem; if not, just retire the dog. It's not a killer unless they want it to be, and it would be a waste of a good police dog.

"I don't think the dog meant to hurt him - it's a dog, it's an animal, if it feels threatened or something it's going to give you a nip."

Mr Hatton said Tyler had not been near a dog since the attack, so he did not know if he was now afraid of them.

"He's quite keen to stay away from dogs for a while. Whether he gets over that is up to him."

A review will decide whether the kindergarten visits will continue, but Mr Hatton said it would be a shame to cancel them.

"We think the programme of putting dogs into the kindergartens is a good thing and we'd hate to see it end just because of this. No hard feelings."