Prime Minister John Key denies that the fight against methamphetamine is being lost but says importations are up from countries where the drug is cheap because of the big profits to be made by gangs.
He told reporters in London on Monday that the government's methamphetamine action plan initiated between 2008-11 had led to a reduction in the drug's use.
"What has changed is there is a lot less of the domestic manufacture because it's so much harder to buy the precursor, pseudoephedrine, over the counter."
But Mr Key said that had led to greater efforts to import the product, with big drug seizures now being reported.