Shocking moment tuk tuk driver appears to signal to thief before they rob his passenger

This is the shocking moment a tuk tuk driver appears to signal to a pair of bag snatchers moments before they robbed the unsuspecting passenger on board.

The incident in the Thai capital of Bangkok was filmed by the victim, Eric Lau, a tourist from Hong Kong.

Lau, who was travelling on the tuk tuk with his new wife at the time, happened to be filming his journey back to his hotel and managed to capture the entire ordeal. The footage has now been submitted to the local police as evidence.

In the video, the tuk tuk could be seen driving along a busy road.

Nothing seems out of the ordinary at first but out of nowhere, two men on a motorbike speeds past the vehicle.

They grab Lau's bag as they ride past and are gone in a matter of seconds.

In a slowed down version of the video, the tuk tuk driver appears to gesture shortly before the bag snatching took place although it's not clear whether he was just moving his hand from the steering wheel.

Within moments, two men on a motorbike rode past the tuk tuk and grabbed Eric Lau's bag from in front of him. Photo / GOTrip, Facebook

A caption on the video also claims the driver slowed down the vehicle moments before the robbery.

The incident took place on June 30.

Lau posted the video onto Facebook on July 1 and the footage was later shared on Hong Kong travel site Go Trip.

Since it appeared online, it's had more than 1.7million views with many people expressing their shock at the brazen theft.

According to Go Trip, the bag contained 13,000 Thai Baht ($506) and HK$1,000 ($2297), as well as all of Lau's travel documents.

He has now reported the incident to the police though the thieves are yet to be apprehended.