''The installation of jetties and groins has led to severe coastal erosion in many spots, so we need better control of their construction. Only projects that pose no risk to the coastal environment will be approved,'' said Santi Boonprakub, director of Onep's environmental impact evaluation bureau.

The new ministerial announcement requires developers to study a project's impact on the shoreline in a five-kilometre radius from the construction site, and on marine ecology and nearby communities.

''Of course, this will delay project construction, but it's worth doing it to save our shorelines,'' said Mr Santi.

Coastal protection structures have been widely built by the Marine Department and local administration organisations over recent years due to the severity of coastal erosion, losing vast areas of land each year.

However, it has been found that some of these structures have triggered coastal erosion in other areas.

It has been estimated that the country loses about 5-20 metres of shoreline each year due to coastal erosion. About 30 erosion hotspots have been identified in Samut Prakan, Bangkok, Rayong, Prachuap Khiri Khan and Songkhla.

Marine experts blame human activities, including the construction of breakwaters, jetties, groins, sea walls and deep-sea ports on the devastation of coastal areas.

The Marine and Coastal Resources Department recently commissioned Thammasat University to conduct a study on the coastal erosion situation in the Gulf of Thailand. The study area covers the coastal stretch from Samut Songkhram to Chachoengsao (100km) and Nakhon Si Thammarat to Songkhla (150km).

The department will use the study's findings to come up with measures to prevent coastal erosion.