A four-year-old child has been rushed to hospital in critical condition following a two-vehicle crash on Highway 401 in Mississauga.

The crash occurred in the eastbound lanes of the highway near Winston Churchill Boulevard.

One woman and two children, ages 2 and 4, were injured in the collision, which involved a small SUV and a transport truck.

OPP Sgt. Kerry Schmidt said the four-year-old girl was ejected from the SUV and the other two occupants needed to be extricated after becoming trapped inside the vehicle, which ended up on its roof.

The four-year-old was transported to a trauma centre with life-threatening injuries. The two-year-old and the woman, who sustained only minor injuries, were also taken to hospital for treatment.

Schmidt said car seats were present inside the SUV but police will be investigating to see whether they were properly secured.

The eastbound lanes of the highway have been closed at Winston Churchill Boulevard for the collision reconstruction.

Schmidt said the highway will likely be closed for several hours.