A 60-year-old Auckland businessman has been remanded in custody after he was charged with attempted blackmail for financial gain over a threat to contaminate infant milk formula with 1080.
The man - who has interim name suppression - stood still and silent at Manukau District Court this afternoon, where he faced two charges.
He was arrested by the police this morning, who carried out five searches as part of Operation Concord.
He was remanded in custody, and will next appear in court on 28 October.
The charges could result in a maximum prison term of 14 years.
Commissioner Mike Bush and Detective Superintendent Andy Lovelock called an urgent press conference about the investigation earlier this afternoon.
Police said they believed the accused had acted alone.
Mr Bush said the investigation had been long, complex and comprehensive, involving a 35-strong team, and had considered 2600 members of the public.
The total cost to date has been over $3 million.
Mr Bush said that they were not able to put any more information into the public domain.
"We appreciate that there will be many questions about the investigation and the threat, however we are mindful of any judicial process to come as well as the investigative activity which is still ongoing.
"What we can say is that today's development sends a clear message that we will use all necessary resources at our disposal to investigate such threats, no matter how long it takes."
In November 2014, Fonterra and Federated Farmers received anonymous letters that threatened to contaminate infant formula with 1080 unless the New Zealand government stopped using 1080 for pest control by March 2015.
Small packages of milk powder were included with the letters, which tested positive for a concentrate form of the poison.
The scare made international headlines, due to its potential impact on the multi-billion diary industry.
Ministry for Primary Industries (MPI) head Martyn Dunne has credited the police for their diligent work in making an arrest.
He said testing regimes introduced after the threat to poison infant formula would continue, despite today's arrest.
Mr Dunne said they had carried out more than 150,000 tests across a range of products since the threats were made.
"The testing regime will continue. Because the systems are now in place, many of the manufacturers will use that process, just as ongoing food safety measures."
He said it ended a threat to the most vulnerable people in New Zealand and overseas.
Speaking at the news conference today, Mr Dunne said the main focus had always been consumer safety.
"Today, mums and dads should be confident that infant formula and the food that's involved in the industry is as safe today as it was then."
Mr Dunne said since the threat, a large number of testing regimes have been put in place.
Fonterra chief executive Theo Spierings said the company was also pleased to hear of the arrest.
In a statement, Mr Spierings thanked the police and MPI for what he said were continued and exhaustive efforts on behalf of the New Zealand dairy industry, retailers and the general public.
He also acknowledged the significant response from the dairy industry to the threat.
Prime Minister John Key has congratulated the police for making an arrest
He said while it was always likely it was a hoax, the case had to be taken seriously.
"With that potential of that person being out there, and therefore the remote risk that it could have been carried out, it's deeply worrying. So I think the police ought to be congratulated, they've done a good job of staying on the case - and it's a very complicated case as I understand it - and we'll see now how it progresses as it goes through the courts."
The head of the Infant Formula Exporters Association, Michael Barnett, said some New Zealand companies have gone under as a result of the 1080 scare.
Mr Barnett said New Zealand producers have lost out, particularly in the Chinese market.
"The impact for the small and medium guys when you look at the China market, they've carved themselves out a niche there, but they've carved out that niche as a result of spending time in the China market and appointing distributors and understanding the networks over there."
Mr Barnett said their position in Chinese supermarkets have been taken over by France, Switzerland and Australia.