The police watchdog says the placement of an officer's knee on the side of a youth's head during an arrest was unjustified.
The incident took place in Upper Hutt in January last year after a car tried to evade an alcohol checkpoint.
The car pulled into a driveway, where police spoke to a youth who was found to have stolen the car and was driving while disqualified.
A complaint was subsequently lodged alleging the youth was punched in the face, thrown to the ground, and that officers failed to listen when he told them he was having difficulty breathing.
But the Independent Police Conduct Authority (IPCA) has found the use of force to take the youth to the ground following his arrest was justified and proportionate.
Video footage showed the youth was not punched in the face and was brought down in a reasonably controlled manner given the circumstances.
While the youth was on the ground, the officer's knee can be seen placed on the side of his head.
The IPCA said this was unjustified even though there was minimal force applied by the officer.
"The footage shows the youth made no genuine attempt to get up from the ground.
"Therefore, the placement of the officer's knee on his head was entirely unnecessary," IPCA chairman Judge Colin Doherty said.
The IPCA also found the officer should have submitted a Tactical Options Report in relation to the force used to take him to the ground.
Police acknowledged the findings.
In a statement, police said the driver failed to comply with police instructions and became abusive and resisted arrest.
The driver was physically bigger than both officers on the scene.
Wellington District Commander Superintendent Corrie Parnell said the use of force was an absolute last resort.
Both officers made attempts to calm the driver and diffuse the situation to no avail, Parnell said.
"This officer was faced with a driver who was actively resisting arrest.
"I am confident they have learned from this incident and will apply these lessons when making tactical decisions in the future."