The Marine Department has been ordered to retrieve within 15 days the vessel Por Andaman 2 that sank in the Gulf of Thailand off Chumphon province.
The department's deputy director-general, Phuriphat Thirakunphisut, on Friday said Thai Laemthong Fishery Oil Trade Co Ltd, owner of the sunken ship, is preparing for the salvage operation, which will be conducted by experts to reduce the environmental impact.
The department is also preparing buoys ranging 600 metres to contain the spill as well as 600 litres of dispersants, Mr Phuriphat said.
The incident has been classified as a tier-2 emergency.
Mr Phuriphat said the navy has deployed a remotely operated vehicle for underwater exploration around the sunken ship.
After obtaining sufficient information, the navy will plan operations for pumping oil out of the ship. Operations will begin in one week after samples of the spill have been collected and assessed by the department's security and marine environment office.
The Chumphon branch of the Marine Office has directed patrol boats to search for spillage and appraise damages, as well as warn people against sea travel in the area.
Mr Phuriphat said an inspection revealed the vessel did not have insurance, as the vessel type was considered ineligible for coverage.
The department's Legal Affairs Bureau is studying how this type of vessel to take out insurance. This would help facilitate the work of authorities in similar incidents, he said.
After its own assessment, the Pollution Control Department has determined the spill will not affect land along the coastline.
The Prachuap Khiri Khan branch of the Marine Office insisted that water discolouration along Bankrut Beach in Thap Sakae district is not related to the oil spill.
An examination showed the discolouration was attributed to a plankton bloom, a common phenomenon that turns seawater an unusual shade of green. The event occurs every three to five years, mainly caused by wastewater.