Tasering a man who was lying face down on the ground was "disproportionate and unjustified", the Independent Police Conduct Authority says.
The authority released its report today into the incident in Christchurch on 1 April 2016.
Police said the man had been in a fight and became agressive with police, refusing to answer questions or obey instructions.
He was tasered twice and pepper sprayed while the officers were attempting to arrest him.
Then when the man was lying face-down on the ground, he was tasered again by a probationary constable.
The authority found the first two uses of the taser were justified, but the third was for compliance which is a breach of policy and amounted to excessive force.