PTTEP was taken to Australia's highest court in June last year by 15,000 Indonesian seaweed farmers over the historic Montara oil spill offshore Western Australia in the Timor Sea.

On August 21, 2009, the Montara-H1 well blew out on the wellhead platform. An uncontrolled spill continued spewing between 400-2,000 barrels of oil per day until November 3, after a relief well was drilled and the leak stopped.

The plaintiff seaweed farmer class action alleges damages to crops and subsequently livelihoods caused by the oil spill, which they claim reached the coast of Indonesia.

The farmers are claiming damages of more than A$200 million.

PTTEP refute this and in the company's annual report released a few weeks ago said it maintained its position that no spilled oil from Montara reached the shores of Australia or Indonesia.

The company also maintains that there was no lasting impact on the ecosystem and biodiversity in the waters.

The trial was expected to last between six and 10 weeks, however painstakingly dragged on for several months.

Lawyers for PTTEP attempted to have expert evidence thrown out of the trial last November, however the judge ruled in the Seaweed farmers' favour.

The defence also attempted to to block the plaintiff from using the term 'oil' during parts of the case on the basis that seaweed farmers were not suitably qualified to identify hydrocarbons. 

Hearings continued through December where the court heard from the seaweed farmers and a range of other experts including oceanographers, satellite imagery analysts, chemistry and toxicology experts.

The Indonesian seaweed farmers are represented by Maurice Blackburn and PTTEP is represented by top-tier commercial litigators from Allens.

Justice Yates is yet to deliver his judgement on the matter. A timeframe on the judgement is unknown, and could take several months to be delivered.

PTTEP no longer owns the Montara oilfield, after it sold the field to Jadestone Energy, which brought the field back into production early this year.