Watch: Look out behind you! Oblivious diver gets fright of his life as monster great white sneaks up behind him

Footage has been posted online showing a large great white shark brushing past a salvage diver who is seemingly unaware of its presence.

The video was posted to the SA Spearfishing Facebook page overnight, saying the diver was looking for salvage and that the video was taken by his son.

In the video, the diver is swimming near the bottom when he turns around toward the camera.

As he does, the shark emerges from behind him in the murky water, swimming past him and avoiding contact by just a few centimetres.

The startled diver can be seen reacting as the large shark, which can grow to weigh a few tonnes, glides past.

Great white sharks can live up to 70 years and swim at up to 56 km/h at depths down to 1200m.

They are considered vulnerable by the International Union for Conservation of Nature due to its late sexual maturity, low reproductive rate and slow growth.

The video has garnered more than 1.3 million views as of 11.30am today.

It is unclear when or where the footage was recorded.