Park chief Narong Kong-iad confirmed that damage occurred in many locations, mostly around Koh Kradan after the island was overwhelmed by tourists.
The tourists were ferried to the island by big tour vessels and long-tailed boats. Large numbers of visitors made it difficult for park officials to supervise beach areas and underwater reefs.
The boats dropped their anchors which damaged the reefs. Some boats remained anchored while the tide was going out, which caused the bottom of some vessels to scrape against the reefs.
The park and state-run marine centre in Phuket are to demarcate areas away from the reefs where boats can moor. Tour operators are also instructed to strictly follow rules on boat mooring and feeding fish around the island.
The problem was brought to light by Facebook posts from users named Prug Udomkerd and Supaporn Prempree.
Messages appeared alongside photos of the reefs close to beaches on Koh Kradan, which showed extensive damage after the tourists had left.
Somsak Panthumet, head of the professional tour guide club in Trang, said he and fellow tour operators and guides have discussed the problem. They plan to consult park authorities on ways to better manage and regulate visitors to the island.
The group also pledged cooperation in rehabilitating the damaged reefs which extend over 500 metres.
Similar destruction was also reported off the coast of nearby Koh Chuek.
Mr Somsak said tourist numbers to Koh Kradan far outstripped its capacity to handle them, particularly during long weekends and public holidays.
Read original story here.