Benn Robert De Hosson, 24, pleaded guilty to a charge of assault occasioning actual bodily harm in Wollongong Local Court on Tuesday after his attack left the victim, Toby Nash, with cuts to his nose and eye and severe concussion.

Court documents said the victim, himself severely intoxicated, was in the gaming room of the Fairy Meadow pub in the early hours of August 10 last year when security guards asked him to leave due to his intoxication.

At the same time, De Hosson and two other men approached Nash in an aggressive fashion. There was a short altercation between Nash and one of De Hosson's friends, followed by a further scuffle between the two groups.

De Hosson, who has a history of committing violent acts when intoxicated, approached Nash and punched him in the left side of the head while he wasn't looking.

Nash staggered backwards and covered his face. He was ushered out of the building before being taken to hospital for treatment.

Police spoke with De Hosson at the pub, who immediately confessed, telling then "I know, I f--ked up".

In court on Tuesday, defence lawyer Paul Cramer said the melee had been preceded by another incident between the two groups in which one of De Hosson's friends had been spat on.

He said De Hosson had problems with alcohol and cocaine but had engaged with Illawarra Drug and Alcohol Services to seek help.

Magistrate Roger Clisdell agreed to have De Hosson assessed for home detention instead of full-time jail.

The case returns to court on June 25.