Rikki Davis, 31, and Shane Davis, 28, yesterday pleaded guilty in Wollongong Local Court to a charge of affray that stemmed from the July incident.

The pair had originally pleaded not guilty to the charge and the matter had been set down for hearing yesterday, however the siblings changed their mind and confessed to the crime.

The court heard the male victim had been walking along the footpath near Rikki Davis's Smith Street home when he noticed the brothers outside the unit block and approached them.

The trio then got into an argument, prompting the victim to pick up a nearby brick in an effort to scare off the brothers. Moments later he threw it in the brothers' direction.

Both brothers, who were well affected by alcohol, began punching the victim in retaliation.

The pair soon overpowered the victim and he fell to the ground before being kicked multiple times in the torso.

Five people who witnessed the assault "feared for their own safety", police documents before the court said.

The brothers left the victim lying on the ground and returned to the Smith Street apartment.

Police arrived on the scene and the victim was taken to Wollongong Hospital.

Lawyer Jane Healey, representing both brothers in court, said the pair had "overreacted" in attacking the man that evening.

She said the men had pleaded guilty to the affray charge on the basis that their actions constituted "excessive self-defence".

"It was a bad night that got worse for them," she told presiding magistrate Susan McGowan.

Ms Healey said Shane had always had a problem with alcohol, however his brother did not, although both men admitted to being intoxicated on the night.

The court heard both men were having trouble finding full-time employment, however Rikki did manage to do casual work.

Magistrate McGowan fined Rikki $850 and Shane $500 and placed both men on conditional bonds, including supervision from NSW Probation and Parole officers.

Shane was also placed on a further good behaviour bond for an unrelated matter.