A self-proclaimed "hunter and adventurer" is being investigated by Northern Territory authorities after he was filmed riding a live saltwater crocodile.

In the video posted to social media at the weekend, Niels Jensen — who describes himself on social media as a Danish hunter and adventurer, living in the Top End as a hunting guide — can be seen goading the crocodile with a dead wallaby.

When the animal takes the bait, Mr Jensen sits on its back, posing for photos.

The Northern Territory Department of Tourism and Culture is now investigating the incident — and whether it was a wild or pet crocodile.

"Saltwater crocodiles are large and potentially dangerous animals," acting director of Wildlife Operations Tracey Duldig said.

Danish hunter Niels Jensen posted the video to social media ( Instagram: Niels Jensen )

"The behaviour shown in this video is dangerous and reckless and we do not support this type of interaction with crocodiles."

Authorities are also probing the use of a wallaby as bait.

"This is a protected species and it is illegal to take or interfere with protected wildlife," Ms Duldig said.

"Heavy penalties can apply … The Department of Tourism and Culture will investigate the circumstances surrounding this incident."

It's not the first time tourists have earned the ire of Top End authorities.

In 2014, a man was dubbed "unbelievably stupid" by park rangers after posing inside a baited crocodile trap at Kakadu following two fatal attacks.