Two young children have died and a woman has been injured after a car ploughed into the trio.

The children, aged under five, were in a pram when they were struck by a vehicle at the intersection of Joseph and Gilbert Street in Cabramatta, south-west Sydney, at 3.15pm on Wednesday.

Paramedics treated the children at the scene, and rushed them to hospital in a critical condition before they died.

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

The 56-year-old driver was uninjured and arrested before being taken to hospital for mandatory testing.

The children are yet to be identified.  

A crime scene has been established and investigations are continuing with assistance from the Crash Investigation Unit. 

Cumberland Highway is closed southbound in Cabramatta between Gilbert Street and Coventry Road. 

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

more to come 

Two young children have been left fighting for their lives while their mother has been injured after a car ploughed into the trio 

The children, aged one and five, were in a pram when they were struck by a vehicle at the intersection of Joseph and Gilbert Street in Cabramatta, south-west Sydney, at 3.15pm on Wednesday