The deal will see 170ha of private land containing beech forest and regenerating native bush, in return for 22ha of the Ruahine Forest Park.
Mr Sanson said the decision was a result of the careful assessment of the ecological values of both sites.
As such, he decided to revoke the protected status of the 22ha of Ruahine Forest Park to enable the exchange to take place.
Under the Conservation Act, proposed land exchanges must result in an overall conservation gain for public conservation land and promote the purposes of the act. "I believe this land exchange well and truly meets that test," he said. However, not all parties see the exchange as a "net gain", with Forest & Bird's (F&B) Peter Anderson arguing there is no legal justification for the land swap.
"If it were to proceed we will lose a threatened environment with rare ecosystems and species and be replacing it with land of far lesser ecological value and diversity," he said.
Central Hawke's Bay F&B co-chairman Dan Elderkamp was also disappointed. "F&B will have to look at legal options and possibly challenge it," he said.
When asked about possible legal action Mr Newman was not worried, from HBRIC's point of view Mr Sanson's decision was a robust one. "We are very confident that the decision will stand the test of time," he said.
Whether possible legal action could push back the deadlines of other conditions precedent, Mr Newman said the company would deal with those issues if and when they arose.
In regards to the decision, Mr Newman said it would be constructive for community-based conservation groups to sit down with HBRIC and look at the benefits all parties could derive from this exchange.
Hawke's Bay Regional Council (HBRC) chairman Fenton Wilson also supported it, labelling it "commonsense".
However, fellow councillor Peter Beaven said it was only one of two hurdles HBRIC had to clear and meeting the condition precedent water contract threshold was far more important.
"They have reported for the past three months contracts for 20 million cubic metres of water and that is less than half of what is required.
"For me that is still the biggest challenge that we face to get this thing over the line."
Farming training college Smedley is fronting up the land for HBRIC to buy for the swap, with its board chairman Pat Portas saying this particular tract was offered up because it was all but inaccessible by the school once the dam was in place.
The swap is conditional on the Ruataniwha Water Storage Scheme going ahead.
In a separate decision, the HBRIC will be required to trap and transfer native fish species present at the dam site.
