KEY POINTS:
The number of P labs busted over the past year has dropped - but experts warn the war on the addictive drug is far from won.
Latest police statistics show 115 labs were discovered in the year to October 31, compared with 145 in the same period in 2007.
But police and a P expert are not taking heart from the decrease, saying the number of P labs discovered is only one indicator of the drug's prevalence.
Mike Sabin - a former detective who now runs drug education and advice company Methcon - said several other indicators of P use showed the drug was still widely used, despite positive signs use of the drug had peaked.
"I think we've definitely plateaued, but unfortunately we've plateaued at very, very high levels."
Mr Sabin said the number of P labs discovered was only an indicator of dwindling P use if the decrease was significant.
"If we saw that number at half, or less, I would say then that we're making significant inroads."
Mr Sabin said the other indicators of P use included a drug monitoring survey, which asked people who had been arrested about their drug habits. This survey had showed that P use had stabilised but remained high.
Another indicator was from the organisation that monitors international drug use, the United Nations Office on Drugs Control.
Its 2008 survey rated New Zealanders as the world's biggest users of P, though Mr Sabin said the findings could say more about the sloppy statistics gathering of other countries.
This country provided extremely accurate data compared with others - particularly those in Asia - where P use was known to be high, but data minimal.
Mr Sabin said that since 2004, Customs seizures of Contac NT - a chemical used in the manufacture of P - had increased from one a day to up to five.
Customs estimates it finds just 10 per cent of what is being sent here. Mr Sabin said between 2004 and July 2008, enough Contac NT had been seized to make more than 1750kg of P - worth $525 million.
A recent drugs summit in Wellington revealed 70 per cent of New Zealand's P was made locally.
"That begs the question: if around two-thirds of New Zealand meth manufacture is from local products and there's been enough Contac NT to make half a billion dollars worth of P, where's all that extra Contac NT likely to be going?"
The figures suggested a lot of P that was made was never found, Mr Sabin said.
National Drug Intelligence Bureau head Detective Inspector Stuart Mills said police were also concerned over the increasing finds of Contac NT at the border, and by the drug monitoring survey results and other information, that suggested the supply and demand for the drug remained high.
Mr Mills said that according to the drug harm index - which looks at the impact of drug use on crime - loss of work productivity and the healthcare costs, stimulants which include P cost $403,470 per kilogram produced.
