In July, the Chief Coroner reported that between 40 and 45 people had died as a result of taking the drugs and the then-Acting Prime Minister Winston Peters instructed officials to come up with a plan.
Health Minister David Clark said this is "not the full decriminalisation of drugs recommended by the Mental Health and Addiction Inquiry''.
"There are immediate steps we can take in response to the challenge we face with synthetics. We are considering the Inquiry's recommendations separately,'' Dr Clark said.
The inquiry reported back last week but the government won't formally respond to its recommendations until March next year.
The government has today announced the two most common synthetic drugs (5F-ADB and AMB-FUBINACA) will be classified as Class A, giving police search and seizure powers and making suppliers subject to sentences of life imprisonment.
A temporary drug classification - Class C - will be created for new drugs, bringing them under the Misuse of Drugs Act.
Dr Clark said if the new drugs were proven to be dangerous they would be progressed from the temporary category to a Class A.
But he said said the evidence was that those now classified as Class A, 5F-ADB and AMB-FUBINACA, had been the majority drug involved in deaths.
An amendment to that act will instruct police to use their discretion and not prosecute for possession and personal use where a therapeutic approach would be better.
Almost $17 million will be spent boosting addiction treatment services.
"Under current laws synthetics and other dangerous drugs are killing people and fuelling crime while dealers and manufacturers get rich. The current approach is failing to keep Kiwis safe and can't be continued," Dr Clark said.
"It's time to do what will work. We need to go harder on the manufactures of dangerous drugs like synthetics, and treat the use of drugs as a health issue by removing barriers to people seeking help."
Police Minister Stuart Nash said an increased focus on organised crime meant frontline police were already targeting dealers and suppliers.
"I expect police will continue to prosecute people for possession when appropriate under the guidelines announced today. It is not a black and white exercise to distinguish between users and dealers. Factors include the seriousness of the offence, if there are victims, if safety of others is at risk from the drug use, if there is public disorder, and if the evidence is sufficient to justify a prosecution,'' Mr Nash said.
"We are striking a balance between discouraging drug use and recognising that many people using drugs need support from the health system, or education about harm reduction. We don't want our jails full of people with addiction problems, we want those people getting treatment.''
Mr Nash said there was a clear line between users and suppliers in how they would be treated. He did not know how many would fit into the category of both.
"But if you're supplying and dealing you're going to have a completely different response from police,'' he said.
Today's response was to say that the deaths of New Zealanders was "totally unacceptable", he said.
"I don't think anyone thinks that that is an outcome we want in our communities."
Mr Nash said the powers up until now for police were insufficient to go after suppliers of synthetic drugs and they now have the same power as they do with those "pedalling meth''.
Mr Nash said it was not about "liberalising" but about finding an appropriate response.
"Police aren't going to wave at people as they drive down the street if someone is smoking synthetics, they're still going to be picked up.''
The Green Party said the approach was an "evidence-based step to reduce drug harm, drug demand, and drug supply''.