Strong winds and choppy seas smashed a huge rock in half next to a Thai island.

The Koh Talu islet was battered by the torrential weather last week before it shattered in two off the coast of Krabi province, southern Thailand, on October 20.

Shocked marine officials said the rock formation weighed between 30,000 and 50,000 tonnes. It had plunged onto the sea bead and damaged 20 per cent of the surrounding coral reef.

Fishing boats and divers were warned to stay away from the well-known rock island, also known as Koh Mae Urai, amid fears it could still be unstable.

National park chief Prayoon Pongphan said many fractures had been found in the rock, which they believe were caused over many years of erosion.

He said: "Continuous heavy rains and strong gusts from a storm caused weakened the rock and caused it to collapse. I would also like to remind tourists not to approach the scene. It is dangerous.

“The broken rock weighs between 30,000 and 50,000 tonnes and the breakage damaged 20 per cent of the coral below the surface.''

National park authorities sealed the area between Phi Phi island and Krabi mainland while instructing tourists to stay off the scene. They are currently investigating the collapse and planning how to secure the rock.