New Zealand's highest court is about to hear arguments for and against changes to protected conservation land.
The Court of Appeal's 2016 decision that the Department of Conservation's planned land swap enabling the Ruataniwha Dam in Hawke's Bay was illegal is being contested in the Supreme Court in Wellington from Monday.
The case is being brought by Conservation Minister Maggie Barry alongside the dam company, Hawke's Bay Regional Investment Company.
Environmental organisation Forest & Bird says it will argue the land belongs to New Zealanders and to nature, and can't be traded away for commercial development.
The Court of Appeal held that the minister can't treat public conservation land as if there were a revolving door between protected and not protected, says Forest & Bird chief executive Kevin Hague.
"If this land swap is allowed to go ahead, it will set a legal precedent for over a million hectares of specially protected conservation land, creating the possibility that these areas can be reclassified and destroyed," says Mr Hague.
Ms Barry has previously said the Court of Appeal ruling was being challenged because the effect of the decision on the management of public conservation land was a matter of public importance.
"DOC needs absolute clarity on whether it can consider the broader conservation picture in decisions about the management of public conservation land, or not," she has said.
Progress on the Ruataniwha Dam, which opens the area up to irrigation, stalled with the election of a new council last year. A moratorium on the scheme has ceased any activity on it, with a review currently under way.
The case is set down for two days.