The Maori Party says the announcement of a new marine reserve in Canterbury cuts across Maori customary rights.
Conservation Minister Nick Smith has announced a marine reserve for Akaroa Harbour.
Maori Party MP Te Ururoa Flavell is pleased the reserve excludes an area where local Maori can still gather kaimoana.
However he says Ngai Tahu wanted to set up a Taiapure management regime over the entire harbour, so they would have a say in its conservation.
Mr Flavell says his party will lobby the Government for a review of the Marine Reserves Act to ensure Maori can have a greater say in similar decisions.