The concept of ecocide — the large-scale destruction of ecosystems — has circulated in international law scholarship since the 1990s, and campaigns to add it to the Rome Statute as a fifth international crime have gained momentum since 2021. New Zealand has not waited for the international process. It has gone first, and gone further than any draft international proposal yet tabled.

The Environmental Crimes Act, passed by 76 votes to 45 in Wellington in March 2025, defines ecocide as any act or omission causing severe, widespread, or long-term damage to a natural ecosystem where the actor knew or ought reasonably to have known that such damage was a probable consequence. The definition applies regardless of whether the act was otherwise lawful — a direct challenge to the principle that a resource extraction permit immunises its holder from criminal liability for environmental harm.

Penalties are deliberately severe: individuals convicted of ecocide face up to 20 years imprisonment; corporations face unlimited fines and mandatory remediation orders. A new Environmental Crimes Directorate within the Serious Fraud Office will have investigative jurisdiction, with dedicated powers to compel disclosure of environmental impact data held by corporate defendants.

Farming and mining industry groups have challenged the legislation's retrospective risk implications, noting that activities previously conducted lawfully may now be assessed against the new criminal standard. The government has included a prospective application clause limiting prosecution to acts occurring after the Act's commencement date, while establishing a transitional compliance assistance fund for affected industries.

"We have criminalised the destruction of human life for a century," said Justice Minister Ginny Andersen. "We are now criminalising the destruction of the systems that make human life possible."