Treaty Negotiations Minister Chris Finlayson says he supports a call by Chatham Islanders for customary title over Te Whanga Lagoon.
The 16,000 hectare lagoon is the largest natural feature of the islands.
During Mr Finalyson's recent visit to the Chathams he met with Moriori and Maori leaders to talk about their Treaty settlements.
He says Labour's 2004 Foreshore and Seabed Act created a barrier for both Moriori and Ngati Mutunga groups to include the lagoon in any Treaty settlement.
Mr Finlayson says after reforming the Act he purposely didn't include reference to the lagoon in the new legislation, which left it free for tangata whenua groups to include Te Whanga in their combined Treaty settlement.
He says Moriori and Maori were rightly aggrieved by the Labour Government's decision because Te Whanga Lagoon could hardly be described as being part of the foreshore and seabed.