Two men died and 80 people were critically injured when their bus collided with a truck on the N1 road near Maraisburg on Friday, Johannesburg paramedics said.

"We don't know how many people the bus was carrying, but the majority of the passengers sustained critical injuries," said ER24 spokesman Werner Vermaak.

The accident occurred at 6.00pm and firefighters and paramedics were still at the scene at 8.00pm.

The fire department was at the scene and used the jaws of life to free the trapped passengers.

According to eye witnesses the bus was overtaking the truck when it collided with it on the N1 south near Maraisburg in Roodepoort.

Several passengers were flung out of the bus during the collision and the road would be closed for a few hours, said Vermaak.