The Government is to amend the claim-of-right defence used by the men who attacked the Waihopai spybase so that anyone using it has to have an honest belief that they have an interest in the property involved.
The three Waihopai protesters were acquitted of burglary and wilful damage charges by using the old defence, which allows the defendant to argue they had a firm belief that their actions were legal, even if they were not.
The men admitted deflating a dome at the base but argued that their actions were justified by the greater good of saving lives in Iraq.
Justice Minister Simon Power says the law was never intended to excuse people who took or destroyed property that had nothing to do with them.
But he says in some cases, people truly believe they have a right to deal with their own property in a certain way and they should not be made criminals for it.
Mr Power says repealing the defence altogether would have been too blunt an instrument and this new provision will achieve the desired effect.
Other reasons for adopting the amendment are that it makes the legislation consistent with the claim-of-right defence under common law and with other, international jurisdictions, he says.
Options rejected by the Government included shifting the burden of proof, adding a reasonableness element and repealing the defence altogether.
The amendment will be included in the next omnibus justice bill passed in the minister's name.