Police are defending the actions of an officer found to have acted unlawfully and contrary to their own policy

The police watchdog, the IPCA, found an unnamed officer was unjustified in pepper spraying a man who'd grabbed on to his colleague's leg, while the man was in custody.

The report found the officer should have used less force first, before deciding if he needed to spray him.

Police say the man was very aggressive and strong, and they unsuccessfully tried to reason with him.

Counties Manukau District Commander, Superintendent Jill Rogers, says had the officer not used the spray, it was likely the officers or the man would have been injured.

They did their own investigation and are not taking action against the officer.