Thailand is to close one of its idyllic islands indefinitely as tourists have ruined the environment.

The island of Koh Tachai is part of the Similan National Park and tourists flock to the island for its white sand beaches and coral reefs.

Tunya Netithammakul, the director of the park, said that unless the island is closed off from tourists, Koh Tachai could suffer irreversible damage.

The majority of Thailand's marine national parks close during mid-May and mid-October when the monsoon season hits, but Tacha will not re-open from October 15, according to the Bangkok Post.

Netithammakul is quoted as saying:

Experts said a beach on the island could hold around 70 people, but had experienced numbers up to 1,000, along with food stalls and tour boats.