There's been more criticism of Canadian-owned Nautilus Minerals in its bid to mine the sea-floor in Papua New Guinea.
Nautilus' Solwara 1 mine, planned for the Bismarck Sea, is the world's first commercial deep sea mining project.
But the Deep Sea Mining campaign says there's been a lack of environmental research for the project.
The author of the report 'Out of Our Depth: Mining the Ocean Floor in Papua New Guinea', Dr Helen Rosenbaum, says very little is understood about the possible impacts of Solwara:
"They say they've continued to do research that addressed a lot of the concerns that we addressed in that report. But every time we've gone back to them to say, well can you share this research with us, we've been unsuccessful. So we're totally unconvinced that this research has been conducted."
Dr Helen Rosenbaum says the campaign's concerns are similar for the many projects in which deep-sea mining exploration is starting throughout the Pacific.