A hero teenager waded through a swampy stream filled with water spinach to save an injured dog.

The lad stepped up to help officers from the Siam Phayao Rescue Unit and held a pole with a noose at the end to pull the pooch from the gunge in Phayao province, Thailand, on August 23.

Footage shows the youngster stepping into the waterlogged area with his tool before taking a tumble, then walking back with the animal to safety.

Another rescuer handled the pole when he reached the banks and released the pooch before it was fed by residents and taken to a vet.

There are an estimated 8.5 million dogs in Thailand, of which about one million are strays due to a lack of effective animal control programs and pet abandonment.