The right-wing coalition government’s legal amendment cleared a final hurdle in parliament on Tuesday night by a margin of 67 votes to 53.

The law aimed to prevent civil litigation overriding its climate policy and undermining business confidence, the government said.

It was introduced in response to a lawsuit filed by indigenous Maori climate activist Michael Smith against six prominent New Zealand companies for their contribution to environmental harm linked to climate change.

The law, which effectively ended his legal action, represented a “dark day for democracy”, Smith told national broadcaster RNZ. “If parliament can cancel a live court case, then no legal claim is secure at all once it becomes politically inconvenient.”

Smith’s case named some of New Zealand’s biggest and best-known companies, including dairy farming giant Fonterra.