Two people have died and 10 more have been taken to hospital after a "horror" multi-vehicle crash near Dubbo, in which a truck allegedly failed to stop at roadworks.

NSW Police said they believed four cars, a B-double truck and utility vehicle were stopped at a roadworks site when they were hit from behind by the semi-trailer.

An 18-year-old man was freed from his car and another person was freed from a truck after they had both been trapped for more than four hours.

The 18-year-old was taken to Westmead Hospital with back burns while the other person is believed to have been flown to another trauma hospital in an unknown condition.

Several vehicles were hit from behind while stopped at roadworks on the Newell Highway. ( ABC News )

A roadworker collapsed with shock, while New South Wales Police said seven vehicles were involved in the incident which occurred about 12.30pm about 20 kilometres north of Dubbo.

NSW Roads Minister Melinda Pavey said the B-double truck failed to pull up at a stop sign at roadworks and hit the line of vehicles waiting there.

"This is an absolute horror," she said.

"We had one of our workers collapse with shock, who was working on that site.

"There are innocent people caught up in this."

A fire truck makes its way to the scene of the fatal crash. ( Twitter: @walkerb83 )

NSW Police Superintendent Peter McKenna said all vehicles involved in the crash were travelling in the same direction.

An infant was among the eight people already taken to hospital in a stable condition.

The Newell Highway — a major artery between Melbourne and Brisbane — is closed in both directions and motorists are being urged to avoid the area and to travel via Narromine.