Police are investigating boys at Christchurch Boys' High School over an alleged violation using a toothbrush.

A high school sports trip has ended with a 17-year-old being charged with the violation of a boy with a toothbrush.

Police are continuing to investigate the incident involving members of a top Christchurch Boys' High School (CBHS) sports team this year.

The 17-year-old, whose name has been suppressed, has been charged with sexual violation and will appear in the Christchurch District Court over the next month.

IAIN MCGREGOR/STUFF Headmaster Nic Hill is not commenting after a member of a school sports team was charged with sexual violation involving a toothbrush.

The CBHS team was competing at a national tournament in the North Island when another teenager was overpowered by others at the accommodation.

The victim's clothing was removed and a toothbrush inserted into his anus.

A complaint was made and senior CBHS teachers flew to the North Island centre to deal with the aftermath of the incident. The team was not withdrawn from the tournament and went on to finish their scheduled games.

It is understood the incident led to the expulsion of one boy and the suspension of others, although the school has declined to comment.

Headmaster Nic Hill said he could not comment now the matter was before the courts.

The incident has echoes of the so-called Taradale "broomstick boys" assault, which sent shockwaves around New Zealand.

Seven Taradale High School students – including the head boy, deputy head and head of sport – held a classmate down and shoved a broomstick smeared with Vicks into his anus in 2001.

The attack, at an unsupervised Napier party, resulted in seven top students being sentenced to jail.

Three of the teenagers lodged appeals against their verdicts and jail terms but the Court of Appeal dismissed the appeals, saying it was necessary to take a stand against bullying.

"It was essentially an offence of violence, albeit accompanied by circumstances of indecency," the court said.

"This was a serious case which exemplified a serious social problem."