The police watchdog has found an officer unlawfully tasered an Auckland man who broke his ankle jumping off a balcony to escape arrest.

Photo: NZ Police

Two officers were sent to check on the welfare of the man's children in June last year and discovered there was an outstanding warrant for his arrest for non-payment of fines.

The Independent Police Conduct Authority said the man asked not to be arrested as he had to give his son cancer medication every morning and night.

"The man took the officers into his apartment and showed them the medication, at which point his partner and children arrived home.

"His partner was very upset that Police were there, and subsequently one of the officers decided to arrest the man, partly so that he and his partner would be separated for the night to 'cool off'."

To avoid arrest, the man jumped over his apartment balcony's railing onto the concrete about four metres below and broke his ankle, the IPCA said.

The arresting officer fired his taser at him twice, missing the first time, unaware the man had broken his ankle, it said.

The authority has ruled it was unlawful of the officer to use the taser to carry out the arrest or prevent the man's escape.

"The Authority is not satisfied that the officer fired the Taser to defend himself or others, because the man had just run away from the officers and his partner, removing any imminent threat the officer believed he posed to them.

"Nor did the man pose an immediate danger to anyone else after he jumped from the balcony. Additionally, the officer was not justified in using the Taser to prevent the man's escape."

The police have acknowledged the situation was not handled well.

"Policing can be very unpredictable and our officers are often faced with making quick decisions in rapidly-changing situations.

"I agree with the IPCA that this was a judgement call made under pressure and that on this occasion the officer made the wrong call."

"While the situation was not helped by the man deciding to flee arrest, I would also have preferred it if the officer had given more thought to the stressors evident in the family and to recognising the parents' concerns for their ill-child's needs."

The officer involved has since received further training.