Three off-duty police officers have been charged with assault after they allegedly forced their way into an apartment building and attacked two students.

A criminal investigation was started when the first complaint was received about the incident and the officers were arrested this week.

The three Auckland City constables, Chris Renata 31, Patrick Garty, 32, and Wiremu Bowers-Rakatau, 21, were suspended from duty at the start of last month.

They appeared in the district court on Monday charged with assault, and will reappear on September 21.

They returned to work on August 24 but are not doing their normal duties.

Garty faces three assault charges and Bowers-Rakatau two.

The charges were laid under the Crimes Act, which is more serious than the Summary Offences Act under which Renata's single charge of common assault was laid.

Last year, Renata served in the Solomon Islands and was on jungle patrol when he was stabbed by a man with a machete. His leg was gashed, but he escaped on a quadbike.

The assault charges arose after an incident in central Auckland on March 18 when the three constables allegedly clashed with a group of university students going home after celebrating St Patrick's Day.

The Herald understands the attack was captured on CCTV cameras in High St and in the lobby of an apartment building where the offences are said to have taken place.

One of the students, the son of an Auckland detective, needed stitches to a head wound.

He and two others were walking along High St when one of them got into a shopping trolley. He was pushed for a short distance before it fell over and the group abandoned it.

One of the victims, a 21-year-old commerce student, said the three officers "came after us".

"They were yelling aggressively and asked us what the hell we were doing. They tried to have a go at us so we told them to piss off, but they followed us."

When the students went to go inside the apartment building, the constables "pushed their way through the door into the lobby".

The 21-year-old student alleges it was here the three men punched and kicked him and his mates and "went to town on my friend".

"They never once mentioned they were cops."

Chris Renata: One charge of common assault.
Patrick Garty: Three charges of assault under the Crimes Act.
Wiremu Bowers-Rakatau: Two charges of assault under the Crimes Act.