Thai oiler PTTEP, which was responsible for the massive Montara oil spill in Commonwealth waters off the northern coast of Western Australia, is facing allegations from 15,500 Indonesian seaweed farmers who are claiming damages for destruction of their crops caused from spill.

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 into the Timor Sea until November 3, 2009 after a relief well was drilled and the leak was stopped.

The thousands of seaweed farmers, from Indonesia's East Nusa Tengara province, allege that the spill significantly hindered lucrative seaweed farming areas and are seeking damages for the immediate destruction of their crops caused by the spill and an alleged subsequent decline in production caused by oil pollution.

The court case is expected to run for 10 weeks and the class action is seeking over A$200 million worth of compensation from operator PTTEP.

The seaweed farmers are represented by law firm Maurice Blackburn. PTTEP is represented by firm Allens.

"Our experts contend that approximately 6,000 barrels of oil per day contaminated the sea - that's akin to pouring over 70 million litres of sludge into the ocean over the months that the environmental disaster dragged on for," Maurice Blackburn managing principle lawyer Ben Slade said.

 "We are now 10 years on from this environmental disaster and the oil company responsible and its wealthy Thai parent continues to deny the devastating impact their oil spewing out uncontrollably for months on end had on Indonesian seaweed farmers."

Lead plaintiff for the action is Daniel Sanda. Sanda's case claims that the seaweed industry in Rote Ndao and Kupang, Indonesia was destroyed by the oil company's failure to safely operate the Montara Wellhead.

Over 30 Indonesian witnesses - including seaweed farmers who witnessed the oil arrive and destroy their crops - and several internationally renowned experts on oil spill modelling, chemistry and environmental impact will give evidence in the trial.

Seaweed - known as "green gold" in local communities in Indonesia - transformed the region in the early 2000s after the aqua cultural resource sparked new opportunities and development for Indonesian towns across the coast.

Late last month during an interlocutory hearing, PTTEP objected to the seaweed farmers using the word "oil" throughout the case.

PTTEP argued that the seaweed farmers were not qualified to identify oil, according to legal publication Lawyerly.

PTTEP also moved to have an expert's report excluded from evidence arguing that it was based on unreliable data and hearsay from the seaweed farmers.

Law firm Allens declined to comment when contacted by Energy News.

Justice David Yates is presiding over the case.

PTTEP no longer holds the Montara oil field, having sold the field to Jadestone Energy, which brought the field back into production early this year.