A man has been charged with threatening to kill over messages posted online about attacking mosques ahead of the anniversary of the Christchurch terror attack.
The 27-year-old man is due to appear in Christchurch District Court tomorrow.
Canterbury district commander superintendent John Price said police arrested two people today following threats made on internet site 4chan about Christchurch mosques. The other man was released this evening without charge.
Price said he understood the message had been removed from 4chan.
"I just want to reinforce we take these matters extremely seriously and we are also working very closely with our Muslim community," he said.
"Any threat made on our community and our people is a threat on our society and will not be tolerated."
He said the Muslim community was spoken to "pretty soon" after police were made aware of the threats.
Fifty-one people were murdered and a further 40 injured at the Al Noor and Linwood mosques on March 15, 2019, in the worst terror attack in New Zealand's history.
"Any message of hate or people wanting to cause harm in our community, they will be held to account," Price said.
Police were notified through a member of the public coming forward a couple of days ago, he said.
He said an "intensive investigation" happened between when the tip came in and today's arrests.
"We had a full-time dedicated team working on that from a technical perspective and an enquiry perspective."
The only charge the man is facing right now is the threatening to kill charge, but Price anticipates there will be more charges considered.
Price could not comment on the nature of the threat.
He said the threat was credible enough that police took action straight away.
"It's very concerning for me and for New Zealanders as a whole. Most New Zealanders are peace-abiding. Most New Zealanders want us to be united and respect the diversity of New Zealand. Any threat, anyone wanting to do contrary to that, is not the New Zealand way.
He said police are not looking at anyone else in regard to the matter.
Muslim Association of Canterbury spokesman Abdigani Ali thanked police for identifying the threat and acting promptly while "working in collaboration with the Muslim leaders in Christchurch".
"There is no place for hate rhetoric and hate crimes in our country and every community, no matter their race or beliefs, should feel a sense of safety and belonging."
Police raided the property in the Christchurch suburb of St Albans today. Officers could be seen taking computer equipment from the property and loading it into police vehicles.
The second anniversary of the attack on the mosque is approaching later this month.
About the police response at the memorial event, Price said in Christchurch there will be visible staff at the mosques and in the wider context of the event, and police "out and about" on the streets.
Brenton Tarrant, 30, admitted murdering 51 men, women and children at two mosques. He also admitted 40 charges of attempted murder relating to the two attacks - and pleaded guilty to one charge of engaging in a terrorist act laid under the Terrorism Suppression Act 2002.
He was sentenced last year to life in prison without parole.