One of the architects of the Resource Management Act says the Government's proposed changes will seriously undermine environmental protection.
Sir Geoffrey Palmer acknowledges that many of the proposals will deliver improvements, but says planned changes to sections in part two of the act concerning protection of the environment could have dire consequences.
Sir Geoffrey, a former Labour prime minister, said the Government wants to combine all matters in these sections into one set of principles and, in the process, deleting other important principles which would seriously weaken the act.
He told Radio New Zealand's Morning Report programme on Monday the Government wants to alter the part of the act where protection for the environment is enshrined.
Sir Geoffrey believes if this is changed, it would undo 22 years of precedent in the Environment Court and other courts.
But Prime Minister John Key defended the proposed changes, saying they are necessary because the legislation is not working well.
Mr Key said the Resource Management Act is cumbersome and slowing down development. He said the Government has gone through a substantial process to review it and Environment Minister Amy Adams is being cautious about what she is promoting.
Greens call for re-think
The Green Party says the Government should re-think its proposed changes to the Resource Management Act.
Environment spokesperson Eugenie Sage said on Monday the Government's proposal gives much more weight to economic matters and strips out environmental criteria.
Ms Sage said the Government is planning to collapse Sections 6 and 7 of the act into one and preservation of the coast, outstanding natural features in landscapes, and significant indigenous vegetation may no longer be seen as matters of national importance.
Ms Sage said the changes would make it harder for people to have a say on environmental issues.
The Labour Party said it would repeal any changes to the act.
The Fish and Game Council believed that the changes would make interpreting the act very difficult.