Hundreds of mystery starfish appeared on a beach in southern Thailand.

Rojana Boonchuwong was walking along the shore in the Hat Noppharat Thara - Mu Ko Phi Phi national park in Krabi province on February 6 when she spotted the bizarre creatures lying on a mile stretch of sand.

The starfish were deep red or pale yellow in colour, and had dark protrusions dotting their arms and bodies. Amazed at their unusual appearance, Rojana took photos of them.

They are known as 'chocolate chip sea stars' because of their black horns that resemble chocolate kisses. The spikes provide protection from predators while they lie in warm, shallow waters where they are usually found.

Locals said the tide was low this time of the month, revealing all sorts of sea grass, corals, and other marine animals along the coast.

Rojana said: 'I thought of posting pictures on social media to invite other people to see the stunning sight. The starfish and the sunset were amazing.'

She added that tourists should avoid touching or collecting the sea stars, which are protected animals inside the national park.

Violators may face fines reaching 500,000 THB and may also be arrested if they damage wildlife in the area.