The group, Friends of the Earth, in New Zealand supports Kiribati's decision to declare the Phoenix Islands as the world's largest protected area.
The Phoenix Islands are located about halfway between Fiji and Hawaii.
The zone is 185,000 square kilometers and consists of underwater mountains, coral reefs and has more than 520 species of fish.
The organisations co-director, Bob Tait, says Kiribati made the right decision.
"We think that's great. There's been a lot of fish stock depletion around the Pacific and marine reserves, that's well established, that they provide a spawning ground and it's a way back for restore their fish stock in the region. it'll mean less reliance on imported processed products if the locals are still able to fish around the reserve."
Bob Tait says the zone might also attract tourists.