A mother and her four-year-old son have been crushed by a car in a freak accident outside a Bunnings store in Melbourne’s north-east.

Police say an elderly driver accidentally hit the gas and struck the pair at Chirnside Park at about 1.40pm.

The four-year-old child and 30-year-old woman were taken to hospital with serious leg injuries.

A 79-year-old male driver was taken to the Maroondah Hospital where he is being treated for shock.