Up to 30 people were involved in the melee on Gibralter Avenue just before 11pm.

NSW Ambulance paramedics said an 18-year-old woman suffered a head wound and was taken to hospital in a serious condition.

Witnesses said the teen was hit with an empty beer bottle and a fence paling.

It’s understood she was taken to Shellharbour Hospital.

Paramedics also treated a 19-year-old man who sustained a deep laceration to his forehead in the brawl.

It is understood he was taken to Wollongong Hospital.

Witnesses said some partygoers became involved in the brawl while attempting to break up the fight.

Responding police blocked the road between Riverside Drive and North Kiama Drive to traffic before asking partygoers to leave.

The crowd dispersed at about 11.30pm.

Update, 3pm: Lake Illawarra’s Sergeant Ellen Jackson said police had charged a 47-year-old man from the Kiama Downs area. 

The man is due to appear before Kiama Local Court on December 3, charged with malicious damage and armed with intent. 

Police will allege the injured teenage girl was knocked unconscious with a fence paling. 

Police arrested the man soon afterwards. 

Sgt Jackson said police may yet lay more charges. 

”Police still making further inquiries, because of the number of people involved,” she said.