More than 1800 clandestine methamphetamine labs have been found in New Zealand since 2000 - the majority in the upper North Island.
But police say they are "getting traction" when it comes to shutting down methamphetamine and the people who make and sell it, and expect to find far fewer labs in the next decade.
Police figures provided to the Herald under the Official Information Act show that between 2000 and 2012, 1809 meth labs were discovered across New Zealand.
The districts with the most were, in order, Waitemata, Counties Manukau, Waikato, Auckland, Bay of Plenty and Northland.
Canterbury ranked about midway and the Southern and Tasman districts in the South Island were at the bottom of the list.
Since 2005 the number of labs found has been tracking down, slowly, decreasing from 204 to just 94.
A dedicated clan lab team was established in 2004 and continues to work from Police National Headquarters. Since they started work they have also been recording where each lab was found. Most labs are set up in residential houses, but many are discovered in vehicles, commercial buildings and on farms.
Assistant Commissioner Malcolm Burgess believes the drop in numbers comes down to meth manufacturers taking note of the harsh penalties being handed down to those who are caught.
"Whole labs have decreased since 2005. Meth manufacturers have changed their modus operandi in response to the strong penalties handed down," he told the Herald.
"Nowadays we are more likely to find partial labs known as 'clan lab assessments'. The chemicals might be kept in one or more places, and the actual process is carried out somewhere else.
"While this makes it more complex for police to detect operations, it indicates offenders are fearful of being caught and will go to great lengths to avoid detection."
He said labs were more likely to be found in the North Island because that was where the greatest demand for the drug was.
"Labs, like other businesses, tend to be located close to population-dense locations because that's where the demand and therefore the markets are," Mr Burgess said.
"The supply will be greatest where the demand is greatest. Southern is the least populous of the districts and demand is less than in the north."
While there was still demand for meth, the market in New Zealand had stabilised.
"There has been three years of consistent focus from police and other agencies on methamphetamine and there are signs that we are getting traction on the problem. However we will continue to focus on how we prevent the spread of methamphetamine," said Mr Burgess.
"As it stands now, our intelligence is that the price of meth remains high but steady, which indicates that supply is stable with fewer new players coming into the market to make more of the drug.
"However it is difficult to predict with any certainty what might happen in the future. Given the trend for partial labs to be used for the job of cooking methamphetamine, it is likely that the detection of full clan labs will continue to decrease. As already mentioned, the offenders can be adaptable and we need to work to stay ahead of them.
"There has been some initial traction gained by focusing on disrupting the supply of precursor materials. Banning pseudoephedrine is an example of this.
"However the bulk of precursors are imported from outside New Zealand. We are working on strengthening our relationships with industry here and with overseas sources of precursor chemicals.
"Limiting the availability of the ingredients needed to manufacture methamphetamine is key to disrupting the supply of the drug."
Mr Burgess said that historically, the Waitemata district had a higher number of meth labs located. But recently the spread had become more even over the greater Auckland area.
Waitemata District Commander Superintendent Bill Searle said his staff had been focusing on meth labs for a number of years. The number of labs found in his district had dropped from 54 in 2005 to just 13 last year.
"The reduction in the number of labs located is being attributed to both internal and external factors. For example, we have noticed more labs are being located in rural areas which is likely to be a response to increased enforcement by police," he said.
"Internally we have become more prevention-focused. For example, the district has improved its processes, particularly in relation to intelligence gathering and deployment, which is also likely to have had a positive effect on the number of clan labs located. The district will continue to target criminals associated with the manufacture and distribution of methamphetamine to apprehend offenders."
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