UPDATE: Truck driver may have crossed into traffic, prompting six-car Gold Coast pile-up

A delivery truck driver who apparently crossed into oncoming traffic may have prompted a six-car pile-up on the Gold Coast this morning.

The driver was trapped as other motorists rushed to pull her from the crumpled cabin on the side of the M1 motorway.

The first collision sent a car spinning and exploding into flames. Another two cars and a van were struck, after which they swerved off the road.

Eight people were injured in the crash, including a six-month-old baby boy. 

The truck driver was rushed to Gold Coast Hospital in a critical condition, where she is being treated for chest and leg injuries.

The M1 was blocked northbound for 3.5 hours, and up to 20km of traffic. Some cars were stuck in traffic for up two two hours, as police worked to clear the site.