The two groups join 18 others including Islamic State that have been given an official terrorist designation, making it illegal in New Zealand to fund, recruit or participate in the groups, and obligating authorities to take action against them.
The U.S. groups are not known to be active in New Zealand, although the South Pacific nation has become more attuned to threats from the far right after a white supremacist shot and killed 51 Muslim worshippers at two Christchurch mosques in 2019.
The New Zealand massacre inspired other white supremacists around the world, including a white gunman who killed 10 Black people at a supermarket in Buffalo, New York.
In the U.S., the State Department only lists foreign groups as terrorist entities. But the Proud Boys were last year named a terrorist group in Canada, while The Base has previously been declared a terrorist group in Britain, Canada and Australia.
In a 29-page explanation of the Proud Boys designation published Thursday, New Zealand authorities said the group’s involvement in the violent attack on the U.S. Capitol building on Jan. 6, 2021 amounted to an act of terrorism.
The statement said that while several militia groups were involved, it was the Proud Boys who incited crowds, coordinated attacks on law enforcement officers and led other rioters to where they could break into the building.