More than 65 people are now thought to have died from synthetic drugs, says the Coroner.
The new figure comes as the Drug Foundation urges the Government to act more quickly to introduce a multi-agency early warning system that could prevent more deaths.
In November the number of deaths linked to toxic synthetics was 45-50 since June 2017.
That figure has now jumped to 60-65, with potentially more.
A spokesperson for Coronial Services said there were seven confirmed deaths from synthetic cannabis toxicity and around 55 cases that appeared to be linked.
"There are also a number of deaths where, while synthetic cannabis contributed to the death, synthetic cannabis toxicity was not the ultimate cause of death," the spokesperson said.
The Drug Foundation has been calling since 2012 for agencies to work together better and faster when new drugs hit the streets and the proposal for a drug early warning system was included in the previous government's National Drug Policy with work to begin in 2016.
The proposal has been discussed by the current Ministers of Justice, Customs, Health and Police.
When it announced a crackdown on synthetics in December, including changes to the Misuse of Drugs Act and a stronger focus on treatment, the Government allocated $8m from the proceeds of crime to establish the system.
Officials from agencies including the National Drug Intelligence Bureau, Health, Police, Customs and ESR have been working on it.
But Drug Foundation executive director Ross Bell said little action had materialised so far.
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"The lack of action and urgency from government departments continues to frustrate. These systems have existed in Europe for 20 years. This is not rocket science," Bell told the Herald.
"They should have done it in 2016 when they promised they would. It's in the National Drug Policy and we kept saying to the government then, 'you've got this action, you say you are going to develop an early warning system by 2016. Where is it?'," he said.
The system has been proposed to work in the same way as Operation Bates, a multi-agency operation that swung into action in Porirua and the Greater Wellington area in late 2016 and early 2017 when there was a spike in callouts to emergency services for people who had consumed synthetics.
Bell said if a drug early warning system had been up and running when it was meant to have been, "the synthetics crisis that we experienced when those first drugs had been identified at the border, even before they made their way on to the street, we would have been in a position to act".
"We're not arguing for an early warning system because its a nice policy-wonkery thing to have. You have these things so you can quickly detect issues and respond to those issues," he said.
The numbers of people dying from using synthetics prompted three public warnings from Chief Coroner Judge Deborah Marshall in a year, but Bell says the big numbers still haven't triggered the response it would expect.
"Imagine if New Zealand was confronted with the opioid crisis, would we ready to identify that and then act?
"The synthetics deaths were a good example. It took a really long time to get information out of police. But even then there was no action," he said.
Health Minister David Clark said officials were reporting good progress in establishing the drug early warning system.
"They're working with the National Drug Intelligence Bureau and I'm advised progress is being made on costings, the IT infrastructure and other technical matters.
"Health officials say they're encouraged by the positive support for the project from stakeholders including ESR and Customs," Clark said in a statement.
Traces hint at $58m drug revenue
Traces of drugs found in wastewater samples in Auckland, Wellington and Christchurch indicate an estimated $58 million in drug revenue has been generated for organised crime groups in just over two years, police say.
The estimate comes from the test results from the police wastewater testing pilot.
Since 2016, police have sampled wastewater sites in Auckland, Christchurch and Whangarei for one week each month and tested for methamphetamine, MDMA, heroin, cocaine, A-PVP (bathsalts) and fentanyl, which was recently added.
Since testing began, an estimated $58 million in known drug revenue for organised crime groups had been generated, Police said.
"This represents extensive community harm as many users obtain their money through crime," Police said in the results.
According to the latest results, from August 2018, meth remains the most commonly used drug in all three regions.
Its use is consistently higher per capita in Whangarei and it's almost exclusively the drug of choice there.
Police estimate meth users across the three cities are consuming a combined 1.5kg every week, costing about $2 million a week in social harm.
The three sites have a population of 647,000 people, about 13 per cent of the national population.
Fentanyl, a highly addictive opioid-based painkiller, is a prescription drug in New Zealand but is also used as a recreational drug. It was responsible for nearly half of the US's 42,000 overdose deaths in 2016.
Other findings include:
• MDMA was the second most commonly detected drug across the three sites, with an estimated consumption rate of 600g on average each week
• MDMA was used most frequently in Christchurch while cocaine was found mostly in Auckland
• Cocaine was detected in low quantities on average each week, likely reflecting less demand and supply