ACT wants to repeal the Resource Management Act, new leader Jamie Whyte told the party's annual conference in Auckland.
Mr Whyte said if part of the next government, ACT would try to scrap the 826-page law, which he says infringes on New Zealander's ability to use their property.
Dr Whyte said National has done some work in the amendments it has made while in government, but ACT wants to go further.
"People have tried to fix it, fix it, fix it - but it is inherently an ill-conceived piece of legislation."
The only justification for law of its kind would be to address a serious market failure and if there was no remedy through the common law, he said.
Details of what regime would replace the RMA were sketchy.
There needed to be environmental protections in the law, but they shouldn't violate property rights, Mr Whyte said.
"We may have another environmental kind of a law, but it would be nothing like the RMA in its ambition."
The ACT leader did not say the new scrap-the-RMA policy would be a deal-breaker in coaltion talks with National.