An online video showing two men surfing on the back of a protected whale shark is fast drawing heavy criticism.

In the three-minute video that has been uploaded on YouTube, two men can be seen standing on top of a whale shark, the largest fish in the world, while being towed by a speedboat.

Several men can also be seen laughing in the background as the whale shark continues to follow the boat.

The video, which is believed to have been shot in Venezuela, is being heavily criticized over social media with the Marine Conservation Institute, a non-profit conservation advocacy organization, condemning the act as "unacceptable".

Meanwhile, London's Marine Connection wildlife group posted an online video calling for the men to be "brought to justice".

In a statement, the group said, reported The Guardian: "Wildlife harassment is never a laughing matter.

"What a sad reflection on their attitude to wildlife when, instead of considering themselves fortunate to see this majestic creature in the wild, they choose to participate in a stupid stunt like this.

"As whale sharks are protected – the IUCN (World Constwoervation Union) Red List of threatened species lists the whale shark as vulnerable – these guys should be charged."

Several social media users called on the men to be prosecuted as well.

Whale shark is normally found in warm waters and are docile creatures that are mostly harmless to humans.