He said in Parliament today the ban was an interim measure while the Government worked on a complete overhaul of the Misuse of Drugs Act, and manufacturers would ultimately have to prove the safety of their products before they could be sold.
Mr Dunne inserted the ban into an existing bill, the Misuse of Drugs Amendment Bill, which was drafted with the main purpose of reclassifying methamphetamine precursors ephedrine and pseudoephedrine as class B2 controlled drugs.
That is now in law as well, and means the cold remedies that use ephedrine and pseudoephedrine will be available on prescription only.
Mr Dunne said clan labs used the precursors to make methamphetamine, known as P, and the market was worth about $1 billion a year.
"It is the only illegal stimulant drug commonly manufactured in New Zealand and we have very high rates of use by international standards," he said.
Labour's associate health spokesman, Iain Lees-Galloway, said his party supported the bill but if Parliament was serious about drugs, the Misuse of Drugs Act would be quickly replaced with a new version.
The legislation came in during the 1970s, and since then the drug scene and treatments needed for drug abuse had changed significantly.
National's rhetoric about the war against methamphetamine was "laughable'' because the bill was introduced in November 2009 and had been hanging around ever since, he said.
He estimated the reclassification of prescursors would affect only about 10 percent of the methamphetamine supply.
National's Paul Hutchison said New Zealand probably had the highest use of methamphetamine in the world and it had "highly detrimental'' health effects.
Speaking about synthetic cannabis products, he said manufacturers were "conniving and merciless'' and would stop at nothing to get their products on the market.
The Green Party opposed the bill, with Kevin Hague saying it was a "ham-fisted response'' to synthetic cannabis products.
"Products like Kronic have been on the shelves for five years, there's no need for this urgency...it is a disproportionate response,'' he said.
The ban inserted into the bill had not been to a select committee for public submissions, which was a violation of the parliamentary process, he said.
The bill passed its third reading by 104 votes to 14 with the Greens, ACT and independent MP Chris Carter opposing it.
- NZPA