A snarling mechanical behemoth has knocked crocodiles off their spot as the scariest thing inthe Northern Territory.

A leaf-chomping green waste clearing monster has been attacking the weeds in Fogg Dam, an hour east of Darwin.

The floating harvester is part of a plan to rehabilitate the struggling wetland by controlling invasive species.

It was brought in by a group effort from NT Parks and Wildlife, Friends of Fogg Dam and community assistance.

It is primarily intended to remove the eleocharis sphacelata weed, floating grass mats and melaleucas.

The dam is an important bird breeding area, and is highly rated as a bird-watching site by Australian Geographic and BirdLife Australia.

The mechanical drive for open water is largely designed to encourage migratory birds back to the waters.

Fogg Dam is a leftover from the failed Humpty Doo Rice Project, which was meant to stimulate growth in NT during the nineteen-sixties.

The floating plant-life death-machine is operated by two low-risk prisoners, who are trained by experts at Charles Darwin University so that they have new skills when they depart the prison system.

One prisoner reports that while crocodiles stay well away from the weed-threshing jaws, they do linger near the back of the vessel in the apparent hope that one of the operators may lose their footing.

The follwing video shows the weed-chomper in action;