The plaintiffs challenging the planned deep sea disposal system for the Ramu nickel mine in Papua New Guinea's Madang province have faced threats over their pursuit of the legal matter.
The trial reviewing the validity of the system is due to start this week.
Both the miner, the China Metallurgical and Construction Company and the Government have unsuccessfully tried to overturn the injunction on the construction of the tailings system brought about by customary landowners.
The landowners' lawyer, Tiffany Nonggorr, says that as the trial date has approached, the plaintiffs themselves have been threatened by thugs linked to the government.
"They have been told that they should pull out, that they should get some money themselves for the matter. They have been threatened that if we win, things will go very badly for them. We're extremely concerned about everybody's safety."
Tiffany Nonggorr also says that a member of their legal team has been attacked.