He also said the officer used inappropriate language by swearing at him.
In addition, the boy's mother complained that Police did not offer medical care for his injuries and did not adequately inform her of what happened when they brought him home that evening.
The authority found that the movement to the ground did not result in the injury to the face and that his mother was adequately informed of what had happened when Police took him home.
They stated that the movement was how the knee injury occurred and that medical care was offered to the 14-year-old.
However, authority chair Colin Doherty said while the officer was justified in taking him to the ground in order to safely restrain him, the method the officer used was unsuitable.
"The technique used by the officer was inappropriate and any risk posed by Mr X [the youth] could have been better managed by having the other officer present, assist in taking Mr X to the ground in a safer manner."
Wellington police district commander Corrie Parnell said it is clear the officer took the appropriate action to prevent harm to both himself and the officers present.