Police and the Independent Police Conduct Authority will be holding separate probes.
Martin James Folan had pleaded not guilty in Auckland District Court to six charges of assault relating to incidents when he was working at the Henderson Police Station.
He was accused of one count of elbowing a teenager in the face in a police car, two counts of hitting a man's head against a concrete floor in the police station, one count of kicking a man in the groin or stomach, one count of putting his hands in a choke hold around a prisoner's neck, and one count of kneeing a man in the groin.
A charge of injuring with intent to injure over the knee in the groin allegation was dropped after Judge Roderick Joyce accepted there was no evidence to link Folan's knee to the victim's injury, which required his testicle to be removed.
Nine officers gave evidence against their colleague.
Despite him being found not guilty of any crime, the Independent Police Conduct Authority is still conducting an investigation into the allegations.
Chairwoman Justice Lowell Goddard said the criminal charges against Folan were just one aspect of the authority's investigation.
"Given the number of allegations against Sergeant Folan, the number of independent witnesses, and the serious nature of the allegations, the only appropriate course of action for the police was to prosecute him.
"Regardless of the outcome, the principles and courage of the other police officers who came forward to testify is to be commended.
"From the outset, the Waitakere area commander and the Waitemata district commander took all appropriate steps to deal with these very serious allegations, and they too, are to be commended for their response," Justice Goddard said.
Police National Headquarters chief media adviser Jon Neilson said police would also be conducting an internal hearing to ascertain whether there had been any breach of the police code of conduct.
"It is a normal process. The criminal comes first, then the internal investigation and then any disciplinary action."
The jury of five men and six women returned their verdicts after deliberating for about five hours yesterday and one hour today.
As soon as the jury returned the verdict, Folan rushed to the public gallery and embraced supporters.
He had tears in his eyes when he appeared outside court. He did not speak to waiting media other than to say he was thankful for the support of his friends and family.
His lawyer, Richard Earwaker, made a brief statement: "It's been a tremendous ordeal for him, obviously. He's too overwhelmed to speak so he's not going to be saying anything, but he'd just like to express his gratitude to the jury for getting the right result.
"We've got the result that we wanted and that was justice so that's the main thing," Mr Earwaker said.
Summing up the trial yesterday, Judge Roderick Joyce, QC, told the jury that the accused's position as a police officer must not affect their assessment of the case.
It was the right of every police officer to exercise reasonable force in order to protect themselves or others or to carry out their duty, he said.
"Should the law be otherwise the job of police officers would be made impossible."
While Folan may have been angry during the incidents, that was not a crime.
"Anger is not an offence and it is a reality of life that an angry or spiteful person might still fear assault."
