More than 200 police are under investigation for assault and using excessive force.

Figures obtained under the Official Information Act show 218 officers are the subject of active investigations by Police National Headquarters' professional standards unit. All were on duty when the alleged events occurred.

In recent months, the Herald on Sunday revealed the cases of four West Auckland officers who were stood down after allegations of assault.

In May an officer, whose name and rank are suppressed, appeared in court charged with assaulting five prisoners - one of whom had a testicle surgically removed. Last month, Constables Gareth Needham and Alan Douglas appeared in the Waitakere District Court charged with assaulting 18-year-old Josh Hart. And a fourth officer was stood down after assault allegations.

A total of 22 officers from Waitemata District, 30 from Counties Manukau and 24 from the Bay of Plenty are under investigation.

Police Minister Judith Collins said any claims of assault or use of excessive force by police were of concern but added that police "tend to be the subject of allegations which often prove to be unfounded".

Last year, only two officers were convicted of assault. Dunedin Constables Brenton Rooney, 33, and Duncan Hollebon, 37, were sentenced in the Dunedin District Court on Friday to community detention for 100 and 160 hours respectively and ordered to pay their victim, Daniel Wiel, $500 for emotional harm. Rooney also had a 7pm-to-7am curfew imposed for two months.