Forest & Bird president Andrew Cutler said he'd left the meeting with that understanding, which was also reflected in notes taken at the time by his general manager, and he was dismayed by Ms Wilkinson's letter.
"Thousands of New Zealanders marched down Queen St because they were concerned about mining on conservation land and we believed the Government had taken on the message that the public wanted conservation land to be protected from mining.
"We think it's disappointing for all New Zealanders who marched to have this decision made just days after the election."
But through a spokesman, Ms Wilkinson denied making that undertaking to Forest & Bird. She said changes to the Crown Minerals Act were required to enable public notification on access applications and legislation to that effect would be introduced next year.
But West Coast-based Green Party MP Kevin Hague said there was no question Ms Wilkinson had gone back on her undertaking.
While the law currently didn't require notification, it didn't prevent Ms Wilkinson from directing it to occur.
"That's the whole point of the undertaking that they gave. If the law required it, their undertaking would have been unnecessary. What they were saying is they were going to go further than the law required in recognition of the public's extreme interest in what kind of mining activity took place on conservation land."
He also said there was little doubt the proposed Denniston mine was significant.
"It would be the second largest open-cast mine in the country and that's just stage one. They have made no secret about the fact that their intention is to expand from that first stage into an operation that takes over pretty much the entirety of the Denniston Plateau and at that point it's without doubt New Zealand's largest coalmine."
