The Hawke's Bay Regional Council intends to try to acquire conservation land for the Ruataniwha water scheme even if an appeal to the Supreme Court fails.
The council wants to dam 22ha of formerly-protected land, flood it and give the department 170ha of nearby farmland in return.
The Court of Appeal ruled last month the process of acquiring the protected conservation land for the $900 million irrigation scheme was unlawful and ordered the Director-General of Conservation to reconsider his decision on the land swap.
The Department of Conservation (DOC) and the council have jointly sought leave to challenge that ruling in the Supreme Court.
Now the council's investment company, which is responsible for the scheme, has applied to become a requiring authority over the formerly-protected land, which includes the reservoir and dam footprint area.
The council needs requiring authority in order to be able to apply to the Minister for Land Information to compulsorily acquire the land under the Public Works Act.
The investment company's chief executive, Andy Pearce, said it was exploring all options available.
"We are simply exercising our legal rights to take a range of different possible paths, in exactly the same way that Forest & Bird, and other parties, have used the full range of their legal rights," he said.
One councillor opposed to the scheme, Tom Belford, said using the Public Works Act to acquire conservation land would be an "outrageous" step.
It would go against the council's responsibilities, he said.
"The land is protected for a purpose and here we are, as the supposed environmental protection agency of Hawke's Bay, trying to basically circumvent a decision to protect our national environment."
Forest & Bird's regional manager for Hawke's Bay, Amelia Geary, said the move was a show of desperation from the council.
"This does seem to be scraping the barrel," she said.
"HBRIC [Hawke's Bay Regional Investment Company] is obviously desperate, and looking for any option available. If they were to successfully acquire the land off DOC, places that are special to New Zealanders around the country would be up for grabs."