Mr Dunne said that in the 20 years since the RMA was created, the environment was in a worse state by nearly every measure, and government's proposals to facilitate development would make matters worse.
"I do not accept that commercial interests should override the environmental principles of the Resource Management Act."
He added: "While we both agree that there could be useful improvements made in tidying up the process issues within the legislation, the changes to Part Two will create a level of uncertainty which will be counter-productive."
Mrs Turia said the legislation was designed to ensure that New Zealand's resources were sustainable, and the second round of reforms undermined the whole purpose of the Act.
The statement indicated that they were open to negotiation on their support for the reforms, but could they could not back the legislation in its current form.