The young men, aged between 16 and 18, were attacked when a fight broke out at a 21st birthday celebration in Malabar.
“One was to the back, one was to the chest,” NSW Ambulance Acting Inspector Lucky Phrachanh told 9News.
“There was another male that was stabbed in the leg and another that looked like a defensive wound to the hand.”
The injured teens were rushed to hospital, two of them suffering from punctured lungs.
Police said a group of unknown men arrived outside the party on Adams Avenue before an altercation erupted just after 10pm.
“Everyone was going at it. There wasn’t one person who wasn’t throwing a punch,” witness Annabelle Lingwood told 9News.
Ms Lingwood was sitting in her car when the fight unfolded.
“They were attacking each other. It was really aggressive, very violent. And I was like ‘oh my god, I’m going to get attacked'”.
Police are now investigating the incident.
This content first appear on 9news