An Auckland man has gone on trial for manslaughter, accused of helping prise a drunk man's fingers from a balcony railing so that he fell to his death on concrete below.

Michael Manga, 39, denies the manslaughter of his friend Stuart Kingi, 57, who fell from an apartment balcony in the Auckland suburb of Glenn Innes in 2010.

Another man, Barry Harwood, 66, had admitted manslaughter for his part in the death, Crown lawyer Nick Whittington told the High Court at Auckland on Monday, Fairfax reports.

The three had been drinking for most of the day and Harwood became angry when Mr Kingi urinated on himself and on the floor, the court was told.

At Harwood's request, Manga allegedly picked Mr Kingi up and put him on a chair on the balcony, where things escalated.

Mr Whittington said Manga helped lift Mr Kingi, who grabbed the balcony with his hands, and then both Manga and Harwood unhooked Mr Kingi's fingers, sending him plummeting headfirst onto concrete, 3.9m below. He died in hospital the next day.

Mr Whittington said Harwood was not strong enough to lift the victim by himself.

The court was told a neighbour, Clive Head, could see Harwood trying to lift Mr Kingi over the balcony railing, but he appeared to be unable to do so.

Manga's lawyer Jonathan Down said the Crown had a selective view of the evidence, and his client was not involved in Mr Kingi's death.