But he has had an apparent change of heart.
"This Government is dealing with drug use as a health and harm reduction issue," he told the Herald on Sunday.
"In light of this, I've had initial discussions with the Justice Minister about drug checking services.
"Through him, I've asked for advice on the legislative and criminal justice issues around such services."
A spokeswoman for Justice Minister Andrew Little said the request had just been received and no advice had yet been provided.
As it stands, the Misuse of Drugs Act makes it an offence to knowingly permit a venue to be used for drug-taking.
"Section 12 [of the act] was there to prevent people from allowing dealing in night clubs, or having cocaine parties on their yacht," said Know Your Stuff NZ director Wendy Allison.
Police had told Know Your Stuff NZ that its services were not illegal.
"But our existence at events demonstrates that the organisers of the events know that people use drugs there, and that is the sticking point," Allison said.
The latest 2016/17 summer testing results from Know your Stuff NZ revealed that the most commonly possessed drug, MDMA, often turned out to be bath salts. And 10 per cent of LSD tested by the organisation was found to be the much more dangerous NBOMe family of drugs.
Half of those who were told their drugs were not what they seemed decided not to ingest them.
Allison said if an exemption to the law were put through to allow Know your Stuff NZ to offer their drug testing services openly at festivals it would "absolutely" make people safer.
"We would be able to reach far more people, and some of the events that have been unwilling to go down the harm reduction track because they are afraid of the law, would then be able to introduce our service," Allison said.
The issue of recreational drug checking has gained prominence this year after the highly dangerous painkiller Fentanyl was detected in what was believed to be heroin at a music festival in New Zealand in February. The drug is far more potent than heroin and has been linked to drug deaths overseas.
It has also been debated in Australia following the deaths of two people in their 20s from drug overdoses at the DefQon dance music festival in Sydney two weeks ago.
Former Labour Prime Minister Helen Clark is among those who have called for drug checking to be legalised. She said in March that she did not think this approach would "green-light" drug use in New Zealand.