The father of an Upper Hutt woman threatened by her ex-partner was bitten by a police dog when he was arrested by mistake, the Independent Police Conduct Authority (IPCA) has revealed.

Photo: RNZ / Alexander Robertson

The IPCA has ruled that the man's arrest by two police officers in Upper Hutt in January last year was unlawful.

The arrest was made when the officers went to a property in January last year, searching for a man who had threatened his former partner and rammed her car.

The woman's father answered the door and was immediately arrested - despite not matching the offender's description.

Read the IPCA's full report here

He told the Authority he was not being aggressive or violent in any way, but was dragged out of his house, slammed up against the wall and repeatedly told to 'stop resisting'.

He was also bitten by a police dog while being escorted to a patrol car before the officers accepted they'd arrested the wrong person.

The man, who was a former police dog handler himself, told the Authority:

"The handler should never have physically engaged with me and tried to control his dog at the same time, which I believe is what led to me being bitten. In my view this was an uncontrolled bite, as I did not hear any command from the handler for the dog to engage me."

Authority chair Judge Sir David Carruthers said the sergeant involved failed to take basic steps to identify the person he was arresting.

"The events were stressful and humiliating for the man, who was forcefully arrested in response to a criminal act for which he was not responsible.

The Authority concluded that the arrest was unlawful, because the sergeant did not have good cause to suspect the father had committed an offence and neglected to take basic steps to identify the person he was arresting.

Because of this, both officers used excessive and unlawful force to handcuff the man and remove him from his property, said the Authority.

The Authority also found that the dog handler's conduct during the arrest was inappropriate, and that he should not have placed his dog in a position where it was able to bite the handcuffed man as the two officers were escorting him to the police car.

Police decided not to prosecute the sergeant due to "personal circumstances" and the Authority said it agreed with that decision.