Fish and Game is leaving the Land and Water Forum, saying it was being muzzled and prevented from speaking out on environmental issues.
The forum brings together a range of industry and environmental groups, scientists and government observers, to collaboratively manage the country's land and water.
Fish and Game communications manager Don Rood said the organisation was unable to fufill its statutory role to protect the environment, and it was not prepared to abandon its core principles by being part of the group.
He said it had not been an easy decision to make but it felt the way the forum was going was not constructive.
