Tonga's police commissioner, Grant O'Fee, says there is a culture of violence within the Tonga police force.
A video posted to facebook yesterday allegedly shows an officer continuously punching and kicking a boy at a rugby game last Friday.
This comes less than a month after police officers were imprisoned for the manslaugther of New Zealand constable Kali Fungavaka.
Mr O'Fee says over the last two years many officers were dismissed for acts of brutality, conceding there is a problem with violence.
"I'd be a fool to say otherwise. I mean we've had enough incidents in the last two years since I've been here to reveal that there is certainly an issue. It is not with all our officers, I mean some of them are very decent young men and women doing a difficult job the best way they can. But there is a definite problem, there's no denying that. I'm the first to admit it, and the first to admit we've got a long way to go."
Mr O'Fee says offenders will continue to be brought to account and punished, but there is a long way to go to get rid of such behaviour.
"To get that change in the way our officers behave and, I hate the word, but the culture of the organisation, it's gonna take years and years and years, it will not happen in months or weeks or even years, it will take many many years. I guess it's just not the time to lose our nerve, we just have to keep on doing what we have been doing and the change will come but it will take time.".
The officer alleged to have been involved in the video assault has been identified and an investigation has been launched.