A boat has sunk and its driver injured after a collision with a jet-ski off Portarlington.

A 16-year-old Taylors Hill teen was riding a jet-ski about 100 metres off Portarlington Pier when he collided with a boat shortly before 8.30pm on Thursday.

The boat sank.

Its driver – a 25-year-old Hoppers Crossing man – suffered lacerations to his leg in the crash and was treated on the shore.

Police have spoken to both the jet-ski rider and the driver of the boat.

No arrests have been made, but police are appealing for witnesses to come forward.