Thai officials have banned holidaymakers from visiting parts of three popular islands, as they review the impact tourism is having on the local ecology.

The waters off Koh Khai Nok, Koh Khai Nui and Koh Khai Nai are renowned for their colourful coral displays and are popular with day-trippers from nearby Phuket, but the Department of Marine and Coastal Resources (DMCR) claims that up to 80 per cent of reefs there have been degraded and has decided to ban tourists from visiting them.

“A tremendous amount of corals have been damaged and getting them to recover is very difficult,” DMCR regional chief, Watcharin Na, told the Bangkok Post.

Coral reefs around the world have suffered from a mass coral bleaching event this year, caused by a combination of El Nino – a naturally occurring weather pattern – and rising temperatures due to global warming.

It is claimed 80 per cent of the reefs around the islands have been damaged Credit: GETTY

However, tourism activity is heaping even more pressure on these beleaguered ecosystems in Thailand, which is expected to welcome 30 million international visitors this year.

“The reasons for coral damage in the Koh Khai area is from the coral-bleaching process, which occurs naturally, and from human activity,” said Watcharin Na. “This includes the increasing number of tourists, boats that anchor on the corals, people walking on corals while playing in the water, feeding marine animals and catching them to take photos of with them.”

Before the ban at least 60 speedboats a day were visiting the islands, according to the DMCR, which has also closed some of the islands’ beachside shops and restaurants.

Tourists will be banned outright from Koh Tachai due to environmental concerns Credit: ALAMY

According to our destination expert, Tom Vater, similar restrictions are likely to be imposed on other islands in Thailand.

“The government is currently conducting a survey on 40 other islands both on the Andaman coast and the Gulf of Thailand side,” he said. “The surveyed areas include Similan, Krabi, Phuket, Satun areas and Ko Chang/Kood/ Samui. It is likely that some dive sites around these areas will be closed, not entire islands.”

A tremendous amount of corals have been damaged Watcharin Na, DMCR regional chief

The news comes a fortnight after Telegraph Travel reported that tourists would be banned from visiting the island of Koh Tachai in October, due to fears that they were damaging the local environment.

Though these measures will be greeted by conservationists, Vater says the country still has more to do.

“Some of the country's most stunning locations, such as the well known Phi Phi islands, have long succumbed to serious degradation due to too much commerce and resort construction,” he said. “With 30 million international visitors expected this year and a growing domestic tourist industry, the pressure on Thailand's beauty spots invariably increases.”