It happened on Haldimand Road 3 between Highway 6 and Haldimand Road 70 just after 6 pm yesterday.

Police say the father and his two children were travelling westbound on Haldimand Road when the car suddenly rolled into a pond, landing on its roof.

A family member was driving behind in a separate car and pulled the man and his two children out of the vehicle before emergency responders were on scene.

The man in his 30s was taken to hospital with life-threatening injuries. His eight-year-old son and five-year-old daughter were not hurt.

Police are looking at all factors that could have led to this single-vehicle crash.