The Sea Shepherd anti-whaling group says it has given up hope that an inquiry into a collision between one of its boats and a Japanese whaling ship, will lead to the truth.
The Shonan Maru Two and the high speed protest boat Ady Gil collided in the Southern Ocean in January. The Ady Gil later sank.
An Australian inquiry has failed to determine who was responsible for the collision. It says Japan refused to answer any questions.
Maritime New Zealand says its investigation is continuing.
Sea Shepherd says it has lost confidence in the inquiry.
It accuses the Government of stalling the investigation until after the trial of Ady Gil skipper Peter Bethune in Japan later this month.