TEN people have been injured in three separate multi-vehicle collisions during a “hectic” morning for emergency services in Sydney.

A 47-year-old truck driver remains in a stable condition in Westmead Hospital after being trapped in his vehicle for more than an hour after a collision with another truck and two vans on the M7 motorway in Prestons.

The accident, which happened about 7am, resulted in the closure of two of the three city-bound lanes, causing a traffic queue of up to 17km.

The man was treated at the scene by paramedics before being flown by CareFlight’s helicopter to Westmead Hospital.

media_camera A 47-year-old male remains in a stable condition in hospital after a truck collision in Western Sydney this morning. Picture: CareFlight

media_camera CareFlight’s rapid response rescue helicopter rushed the injured truck driver to Westmead Hospital. Picture: CareFlight

media_camera The scene on the M7 near Prestons this morning, following a multiple pile up involving a truck and two vans. Picture: 9 News

At 7.30am, two women were trapped inside an ambulance van after it collided with a garbage truck and a car on Warringah Road at Frenchs Forest just after 7.30am. The pair have been taken to hospital for medical checks, while the garbage truck driver was treated at the scene for chest and neck injuries. The car driver was uninjured.

media_camera A garbage truck collided with an ambulance carrying a patient on Warringah Road. Picture: Seven News

“It was very hectic at the scene,” a NSW spokeswoman said.

Less than an hour later, there was a collision involving at least five cars on the Princes Highway in Waterfall, where paramedics treated four people.

Police say one vehicle went off the road and into the bush and another four cars were across the centre median strip.

media_camera Multiple vehicles have been involved in a serious crash northbound on the Princes Highway. Picture: Seven News

None of those involved suffered significant injuries.

All three collisions happened during the morning peak, as students head back to schools across NSW for the start of the second term.

Over the Anzac Day long weekend, NSW police recorded 371 major crashes and one fatality. More than 14,000 people were issued with infringements for a variety of driving offences.