Buller's most controversial electricity generation proposal heads to the Environment Court in September.
The court will begin hearing appeals against Meridian Energy's proposed Mokihinui dam on September 10 - almost two and a half years after Meridian gained resource consent from a Coast council hearing committee.
The appeal is scheduled to last three months, with just the first fortnight held in Westport. The remainder will be held in Christchurch.
The appellants are Forest & Bird (F&B), the Department of Conservation, West Coast Environment Network and Whitewater New Zealand.
Interested parties include Buller Electricity, Alpine Energy, Electricity Ashburton and Orion New Zealand.
The dam would produce about 100MW of power - enough for 50,000 houses or the West Coast's peak demand. Construction is expected to employ 310 people and take about three years.
Even if Meridian wins the appeal case, it requires approval from the conservation minister because the dam would be built on Department of Conservation stewardship land. Meridian's own board would also have to give the project the green light.
Meridian project manager Chris Evans said the company had done a lot of work on the $350 million-plus project over the past year. The biggest change had been increasing its predator control area from 5000ha to 35,000ha, making it one of the largest predator control areas in New Zealand.
Mr Evans said Meridian proposed calling about 55 witnesses for the hearing. He understood the other parties were calling about 30 between them.
F&B spokeswoman Debs Martin said a larger predator control area wouldn't change the fact the dam would desecrate the environment and ruin a pristine wild river.
"It's going to destroy everything within the dam footprint, but it's also going to destroy the natural functioning of a really important river system that is well connected to a highly natural area."
- The Westport News