Thailand is closing a slew of dive sites to tourists after abnormally warm seas severely damaged coral reefs.

More than half of southern Thailand’s coral reefs are suffering from bleaching due to rising sea temperatures.

The reefs will be closed in seven national parks while Thailand’s Department of National Parks studies finds a way to restore them.

“This is part of an effort to restore the reefs,” said Sunan Arunnopparat, director of the Department of National Parks.

Arunnopparat did not say how many diving spots would be closed or how extensive the reef damage was. He said the diving sites would be shut for an unspecified period.

The bleaching is caused by heat driving out the algae living within the coral tissues.

Indonesia’s Aceh province has also seen 80 per cent of some species die between May and August.

Arunnopparat blames global warming for the bleached corals, but marine conservationists say that unregulated tourism is to blame – touching coral and boats mooring over reefs. Coral can only recover from minor bleaching.

“We did not close all of the national parks, just some of the dive sites. Tourists can still go see the forests and the mountains in these parks,” Arunnopparat said.