A B-double truck carrying compressed cardboard has rolled and caught fire on the Hume Highway at Bookham in the Yass Valley, causing major delays for northbound traffic.
NSW Police, the Rural Fire Service and NSW Fire Services attended the scene.
There were no fatalities or serious injuries.
Both Northbound lanes on the Hume Highway are closed at Berremangra, with traffic diverted through Coolac, Cootamundra, Harden and Burley Griffin Way. Diversions are expected to last at least two hours.
Officer at the scene, Inspector David Cowell said the incident was a reminder to motorists to drive safely, pay attention on the road and not be distracted by devices.
Inspector Cowell said traffic infringements this long weekend will incur double demerit points in NSW.