Winston Peters has called Paula Bennett’s claim the previous government halved adult meth use the "world's best kept secret" during an exchange in Parliament today.
The comment came during question time, after Ms Bennett criticised the Government for shelving National’s Meth Action Plan when it came into power.
Mr Peters was answering on behalf of the Prime Minister who was not present in the House.
"Why has her Government shelved the Meth Action Plan which reduced adult meth use rates in New Zealand by 50 per cent?" Ms Bennett asked.
"On behalf of the Prime Minister, the fact is the statement made by that member is not correct, that is why we are seeking alternative measures, including having the frontline police given the firepower to do the job, in particular having 400 police dedicated to that purpose," Mr Peters replied.
Ms Bennett then pressed home her claim with statistics from a 2015 report.
"Is she aware that the meth action plan did in fact work and it did halve the rate of adult meth use, as it was 2.1 per cent in 2009 and halved to 0.9 per cent in 2015?
"That is according to the tackling methamphetamine indicators and progress report October 2015, and has remained stable since then."
Mr Peters was not convinced by her numbers.
"On behalf of the Prime Minister, that claim is the world's best kept secret, if when we became the Government the meth trade was defeated why on Earth would we devote so much time and so much money to get on top of it and that is what the community has advised us to do," he replied.
After more back and forth Mr Peters went on to say the claim National's plan had halved meth use in New Zealand among adults was "simply not true".
The report referenced by Ms Bennett can be found here, with page 14 containing the data relevant to their debate.