Bracing himself for an attack, a drunk off-duty police officer crouched in a fighting stance in front of a bunch of students before shadow-boxing his way into a corner, a court heard.

Yesterday at a defended hearing in the Auckland District Court, former Auckland city constable Patrick Garty, 32, took the stand and claimed he acted in self defence after following a group of "disorderly" students into a city apartment block on St Patrick's Day last year.

"One of the men said 'Now that we've got you alone we're going to f*** you up'," he told the court.

Garty faces three charges of common assault relating to an alleged altercation with male students he claims pulled the fingers and verbally abused him after he told them to stop fooling about with a trolley in downtown Auckland.

"They pushed it [the trolley] into a wall and narrowly missed a couple of parked cars," he told the court.

His colleague Wiremu Bowers Rakatau faces one charge of common assault and the pair are jointly charged with one more count. Another officer, Chris Renata, is to be tried separately in relation to the incident.

Garty told prosecutor Eilidh Hook he was about "a 6 and a half to 7 and a half out of 10" on a scale of drunkenness on March 17 last year. He had consumed several pints of Guinness and a number of whiskies before heading out to visit Irish pubs on his birthday.

But Ms Hook said another police officer who gave evidence previously said he purposely spoke to Bowers Rakatau and Renata after the incident, because Garty was too drunk. After repeated questioning he conceded he was too drunk to drive. Garty said he was walking down High St when he spotted the students pushing a trolley in a disorderly manner. Concerned they would damage shop windows he called out to them to stop and an "argument" ensued, he said.

"Their attitude straight off the bat was aggressive to us ... swearing and saying 'F*** off' and 'You're a pack of faggots'," Garty told the court.

When the men turned down Little High St, Garty followed, allegedly unaware there were residential apartments there. Earlier in the defended hearing the court heard Garty knocked student Thomas Campbell to the ground outside the Soho apartments, with a "double handed strike to the chest area". Another student, Benjamin Palmer, then opened the apartment doors to allow the group inside, but Garty forced his way inside too.

Ms Hook said Garty then "[had] gone after Palmer", striking him in the chest with two hands and punching him to the head and face.

Garty denied throwing any punches and rejected Ms Hook's assertion he followed Mr Palmer down the side street "to teach him a lesson".

CCTV footage of the night shown in court was not clear enough to discern the alleged disorderly trolley behaviour, with Ms Hook saying it was not disorderly at all. Footage in the apartment block foyer showed Garty crouched down with his arms up at face-level swinging at the air.

Garty admitted seeing Mr Palmer holding his hand to his head, but disagreed with Ms Hook that he was sprawled on the stairway bleeding.

Garty, who now works at a steel factory in Queensland, said he did not identify himself as a police officer that night because he did not think he would be taken seriously.

Bowers Rakatau began giving evidence yesterday afternoon, saying the "situation was fairly heated" and the trio used force to prevent it "going seriously wrong". The hearing is expected to finish this morning when Judge Heather Simpson will reserve her decision.