JAKARTA (Reuters) - Indonesia is preparing to sue a unit of Thailand's PTT Exploration and Production (PTTEP) over alleged environmental damage from the Montara oil spill in 2009, the country's Coordinating Maritime Affairs Ministry said.
The move follows earlier attempts at negotiation that stalled in 2012, and a separate class action suit filed by a group of about 15,000 Indonesian seaweed farmers seeking more than A$200 million ($154 million) from PTTEP Australasia to cover damages from the spill.
A total of about 30,000 barrels of oil were estimated to have spewed into the Timor Sea over 74 days after an explosion at PTTEP's Montara drilling rig off Australia's northwest coast in 2009.
"This relates to Indonesian sovereignty and poor communities whose lives depend on the maritime sector, so we must fight this in a more planned way," Basilio Dias Araujo, Indonesia's assistant deputy minister for safety and security, said in a statement published on the ministry's website.
The Indonesian government and state prosecutors are in the process of compiling evidence and have invited around 50 expert witnesses to support the case, the statement said.
"The Indonesian government has asked PTTEP for compensation through non-litigation channels, but the negotiation process became deadlocked in 2012, so no agreements were reached," Araujo added.
The slick from Montara reached Indonesian waters, and was Australia's worst offshore drilling accident. An Australian government inquiry blamed the spill on systemic shortcomings at the Thai oil giant.
A Bangkok-based spokeswoman for PTTEP, the exploration flagship of top Thai energy company PTT Pcl, said she could not immediately comment on the matter.
"No oil from the Montara incident reached the Australian and Indonesian mainlands," PTTEP Australasia said on its website, citing independent scientific studies, and "there has been little or no detectable impact from the spill on any marine eco-system or species in the Timor Sea."
"There were no lasting negative impacts on the region's biodiversity" from the spill, it said.
PTTEP was fined A$510,000 ($394,000) by a Darwin court in 2011 after pleading guilty to four charges relating to workplace health and safety and failure to maintain good oilfield practice. That outcome "concluded all government legal matters in relation to the Montara incident," the company said.
The Indonesian seaweed farmers from Nusa Tenggara Timur province began their action last August and the next hearing is scheduled to take place in May, according to their legal team. [bit.ly/2nUe2Uc]
($1 = 1.2945 Australian dollars)
Writing by Fergus Jensen; Editing by Richard Pullin