The Maori Fisheries Trust says New Zealand should not join Australia's legal action against continued Japanese whaling.
Te Ohu Kaimoana says differences between pro- and anti-whaling members of the International Whaling Commission (IWC) are best resolved through continued diplomatic negotiations.
The IWC is to consider a compromise proposal that reduces Japan's killing quota in the Southern Ocean, and allows Iceland and Norway to continue whaling.
Te Ohu Kaimoana chairman Ngahiwi Tomoana says if the compromise package is not agreed to at this month's meeting of the IWC in Morocco, he has grave doubts about the future of the organisation.
He says it is unrealistic for anti-whaling countries to expect an immediate and complete stop to whaling.
Mr Tomoana says the recent action initiated by Australia has undermined the current negotiation process.
Last week, conservationists condemned Japan for starting its seasonal whale hunt in the North-west Pacific, shortly before the annual IWC meeting which begins on 20 June.
The whaling fleet has left port to hunt 260 whales, and is due to return to Japan in August.
Earlier this month a 53,000-signature anti-whaling petition was delivered to the Government by environmental groups, calling on it to ban all forms of whaling.
Te Ohu Kaimoana allocates fisheries assets held in trust through the 1989 and 1992 Maori Commercial Fisheries Settlement and provides an advisory service to its iwi constituents.