Two children die after being hit by car on Cumberland Highway, southwest Sydney

A woman who was known to the children — both under the age of five — was also treated the scene for minor injuries.

Two young children have died after being struck by a car on a major highway in Sydney’s southwest.

Emergency services were called to the intersection of Joseph St (Cumberland Highway) and Gilbert St in Cabramatta about 3.15pm on Wednesday.

The children, aged one and five, were hit by a car while in the pram, police said. They were treated at the scene before being rushed to The Children’s Hospital at Westmead in a critical condition, NSW Ambulance said.

A 33-year-old woman known to the children was treated for minor injuries at the scene.

Paramedics and other emergency personnel can be seen treating patients.Paramedics and other emergency personnel can be seen treating patients. Credit: 7NEWS Police said the two children were in the pram when they were hit. Police said the two children were in the pram when they were hit. Credit: 7NEWS

The driver, a 56-year-old man, was uninjured.

He was arrested and taken to hospital for mandatory testing.

7NEWS helicopter footage shows a black car on its side beside the roadway following the crash, while multiple ambulances and emergency crews work at the scene.

Paramedics and other emergency personnel can be seen treating patients, with privacy screens erected on the road.

A crime scene has been established and investigations are underway.

All southbound lanes of the Cumberland Highway have been closed between John St and Cabramatta Rd West.

Motorists are being urged to avoid the area and use alternative routes.