At about 4.20pm on August 22, a 16-year old motorcycle driver and a 17-year-old passenger were knocked off their bike on Parkes Street, Oak Flats as they approached the intersection at Moore Street.

There were three bikes driving along the street and Police believe the motorcycles were unregistered.

Two of the riders managed to avoid a Holden Commodore utility travelling through the intersection, but the third bike collided with the ute. The rider and pillion passenger were thrown from the bike.

The bike continued through the intersection and hit another vehicle travelling west on Moore Street. The male driver of that vehicle was not injured.

The rider was initially found to be unconscious and his male passenger had a broken leg.

The teens were treated at the scene by Ambulance Paramedics and transferred to Wollongong Hospital.

The driver of the ute- a 42-year-old man - stopped and was spoken to at the scene by officers from Lake Illawarra Local Area Command. He was not injured in the crash.

Officers from Southern Region Crash Investigation Unit continue with their inquiries and have appealed for anyone who witnessed the crash to come forward.