The Supreme Court has agreed to hear an appeal on whether the Ruataniwha irrigation project can go ahead in Hawke's Bay.
In August, the Court of Appeal blocked the $900 million irrigation scheme, saying it was unlawful, and ordered the Director-General of Conservation to reconsider his decision to let it go ahead.
The Hawke's Bay Regional Council scheme would dam 22 hectares of formerly-protected land, flood it and give the Department of Conservation (DOC) 170ha of nearby farmland in return.
The council has still not decided whether or not to go ahead with the project, ordering an independent review of it last month.
DOC said its appeal was not about the project but about needing the law to be clarified in terms of how public conservation land was managed.
The hearing will be held early next year.