Most debate at the symposium centred on illegal drugs - something that was challenged by a representative of the NZ Nurses Organisation, who said members were reporting the abuse of prescription drugs by the middle class was an "enormous" problem, but one that was barely mentioned in the national drug policy.
Dunne acknowledged the size of the problem.
"I think the area of prescription drugs is one that is, frankly, is creeping up on us in quite a dramatic way," Dunne said in response. "I think it is a real issue and I think it is something that comes into the ongoing development of the policy work in this area."
Earlier, Dunne, who oversees New Zealand's drug laws, said he would move more quickly on reform if not for the reluctance of National.
He declared himself a strong supporter of Portugal's approach - where possession of up to 10 days' worth of low-risk drug supply results in a referral for health treatment, rather than legal consequences.
"Much of the time and money that would have gone into prosecution can instead be invested into assessment and treatment services, all the while freeing up police resources," Dunne, who oversees New Zealand's drug laws, told the gathering.
"In New Zealand, the Ministry of Health will be exploring further options this year for minimising harm in relation to the offence and penalty regime for personal possession within the Misuse of Drugs Act 1975."
Officials are developing regulations to allow people to access cannabidiol products on a prescription basis, and Dunne said he wanted New Zealand-based clinical trials.
Parliament is likely to next year vote on a member's bill by Green Party MP Julie Anne Genter that would go much further in freeing up supply of cannabis for medical use.
It would amend the Misuse of Drugs Act to make a specific exemption for any person with a qualifying medical condition to cultivate, possess or use the cannabis plant and/or cannabis products for therapeutic purposes, provided they have the support of a registered medical practitioner.
The law change has the backing of Labour, the Maori Party, and Act. National is yet to decide how the party will vote on the legislation, or whether it will be a conscience vote.
Dunne had refused to disclose how he would vote, but raised his hand when the panel was asked if they would support the legislation.
Green Party co-leader Metiria Turei said the issue of drug use was now seen as a health issue, but it was also a human rights issue.
Maori Party co-leader Marama Fox said she was in favour of moves towards decriminalisation of cannabis, but said many Maori were strongly opposed to changing the law because of the harm the drug did to communities, particularly young Maori.
"I've got cousins who are schizophrenic [and] long-term drug users. I've got cousins who have brain tumours, long-term drug users. It is not harmless. And I think if we ignore that part of the conversation then we are not being upfront with ourselves."
If cannabis dealing and use was still illegal, then it needed to be policed consistently, Fox said.
"I could not get a police officer to come to the school when I found out one young man was selling drugs at the school. They didn't even want to talk to him. It's like, what are you going to do?"
