Ngai Tahu has filed another claim with the Waitangi Tribunal because of the Government's Emissions Trading Scheme.
It was among new Treaty of Waitangi claims received by the Tribunal on Monday night, before a deadline of 1 September set by the Government in 2005 for Treaty claims to be lodged.
The South Island iwi previously signed what was described as a "final settlement" with the Crown in 1998.
Ngai Tahu chairman Mark Solomon told Morning Report on Tuesday that the claim is designed to safeguard that settlement.
Mr Solomon said the Emissions Trading Scheme threatens the iwi's plans to convert the forests it received as part of that settlement into farmland.
Former Treaty Negotiations Minister Sir Douglas Graham agrees the new claim is an attempt to preserve the value of 1998 settlement and says Mr Solomon's comments have merit.
Mr Solomon said the iwi face $100 million in penalties under the scheme if the forests are not replanted immediately.
The Government says it is checking whether the Crown had knowledge of the Kyoto Protocol at the time of the Ngai Tahu settlement in 1998. An independent reviewer has been appointed.
Climate Change Minister David Parker acknowledges the iwi will be affected by the scheme, but says the Crown has offered fair compensation.
The Maori Party says it is entirely appropriate for Ngai Tahu to file a late claim over the effect of the proposed Emissions Trading Scheme.
Maori Party MP Te Ururoa Flavell says it will not have been an easy decision for Ngai Tahu to make.
During a debate in Parliament on Tuesday Mr Flavell said the Emissions Trading Scheme jeopardises the settlement reached with the iwi.