Motorists are being warned to avoid Mt Ousley Rd northbound after an accident involving a truck and at least three cars this morning.
The accident occurred about 7.30am, 1.5km south of the Bulli Pass turnoff.
A B-Double truck and at least three cars were involved, but no one is believed to have been seriously hurt.
Paramedics are assessed six people at the scene and five were taken to Wollongong Hospital for further treatment
All northbound lanes reopened about 8.30am but traffic remains heavy.
Motorists are advised to use Bulli Pass as an alternative route north to Sydney.
View Mt Ousley accident scene in a larger map