The crash occurred on the Pacific Highway near the intersection of Shirley Road and Falcon Street about 3.30pm.
At least three children aged between 12 and 14 were injured in the crash.
Emergency crews are at the scene treating the children and it is believed they are in a serious condition.
A CareFlight helicopter is also on the way.
Live Traffic NSW said the Pacific Highway is closed southbound at Falcon Street due to the crash.
Read Related Also: These gaming features didn't exist a decade ago
“Two of three northbound lanes are also closed,” the authority said.
”Southbound motorists are diverting left into Falcon Street. Motorists exiting Falcon Street must turn left onto Pacific Highway.”
Peak hour traffic around the area is expected to be disrupted for some time.
Drivers are urged to use an alternative route.