The Government has made it illegal for anyone to possess high purity 1080 without the appropriate approval.
A regulatory change was signed off by the Governor-General last night to tighten up security of high purity 1080, making it easier to track the distribution and use of the poison.
Possession of the 1080 pellets used to kill possums is not illegal.
Environment Minister Nick Smith said this would strengthen what he said were already robust security measures under the Hazardous Substances and New Organisms Act.
Dr Smith said these changes would make 1080 the most tightly-regulated poison in New Zealand, and would hopefully reduce the risk of the poison getting into criminal hands.
Listen to Nick Smith
Govt told not to go public
Prime Minister John Key said the international community advised against going public with a threat to poison infant formula with 1080.
The threat - to contaminate milk products unless 1080 poison drops stop by the end of March - was made four months ago but only made public yesterday.
The Ministry for Primary Industries (MPI) has conducted 45,000 tests across the entire supply chain - all of which have turned out negative for the toxin. Security has also been stepped up and consumer advice has been issued.
Trading partners were informed several weeks ago.
Mr Key said the decision to go public was advised by New Zealand officials after a number of media inquiries.
"The overall decision was made by myself and a senior group of ministers a long time ago," he said.
"That was because I thought, once you got to the point at which the threat date went beyond that, a), we have a good story to tell, very confident about the safety of the product, b), I think we owe it to consumers to say, look, just be a bit more vigilant because this is out there."
Mr Key conceded there were reasons not to go public - like encouraging people who carry out those sorts of acts.
But he said, on balance, it was decided the public should be told.
"Firstly, over 1000 people knew, the person themselves were going to go public," he said.
"But, putting all of that to one side, I would just pose the question, which would be if we hadn't gone public beyond that point when the person said the threat would be made, then I think New Zealanders would say, well, that's a cover up and you actually owe it to us to tell us."
Listen to John Key
However, Carrickmore Nutrition managing director Christopher Claridge, who is also the chief administrative officer for the Infant Formula Exporters Association, said the industry had always received threats of blackmail.
He said the industry believed the Government should have kept the blackmail quiet.
Listen to Christopher Claridge
Trade Minister Tim Groser said international markets were dealing with the matter in a professional and constructive way.
He was asked on his way into Parliament whether markets were increasing checks on New Zealand products.
"I don't want to jump the gun, I think it's not in our interests for us to try and make any sort of predictions as to what different importing authorities will or will not do, all I can say is that we are being received very constructively."
Mr Groser said information was going back and forth between New Zealand and its trading partners, and any decisions to restrict New Zealand products were up to other jurisdictions.
PM will not give in to threat
Mr Key said earlier today that the use of 1080 would not stop because of the threat.
Fonterra and Federated Farmers were sent a letter each in November containing the blackmail threat and powder. It tested positive for concentrated forms of 1080. No further correspondence has been received.
The Government had to take the threat seriously even though it was likely to be a hoax, Mr Key said - and it would not capitulate to such threats.
"If you capitulated on the back of a threat like this, then when would it ever stop? Ultimately the next issue would be they don't like the GCSB or they don't like something else the Government does."
Mr Key said if there was an effective alternative to 1080 to control possums and stoats, the Government would use it.
Listen to John Key
Deputy Police Commissioner Mike Clement told Morning Report it was a dilemma whether to reveal the 1080 threat against infant formula to the public.
Police had planned to release the details next week, but their hand was forced by media enquiries.
An investigation team, dubbed Operation Concord, has been set up in Auckland and is working with the MPI to identify who is responsible.
Mr Clement said parents should be reassured the risk of contamination was very low, and police were using every investigative technique they had to find out who made the threat.
MPI deputy director-general Scott Gallacher told Morning Report the new tests were in addition to those regularly carried out.
"That in our view gives us the ability to front on this to say that we have every confidence in the product that is on the shelves today, that is being manufactured, and that is being exported."
Food Safety Minister Jo Goodhew said formula from September this year had been available for testing and raw product - the milk - had also been tested.
Listen to Jo Goodhew