People with previous cannabis convictions should be able to supply legal medicinal cannabis and, if recreational use became legal, be offered a clean slate, Green MP Chloe Swarbrick says.
But the National Party say only "fit and proper persons" should manufacture legal cannabis.
Swarbrick's comments follow an email exchange - released to the National Party under the Official Information Act - showing that the Greens had asked Ministry of Health officials to look at proposals for the medicinal cannabis legislation, including one that would "allow individuals with previous drug convictions to manufacture cannabis".
The Greens' proposal never came before the House, but that door has not closed.
Who should be eligible to supply medicinal cannabis will be a key aspect of the Government's new regulatory framework, which will be in place by the end of the year following public consultation.
National's associate health spokesman Shane Reti said medicinal cannabis manufacturers and employees should be "fit and proper persons".
National has proposed clean slate legislation requiring no terms of imprisonment and no convictions for seven years for employees, and even tougher standards for licence holders including no associations with gangs.
"The industry was adamant that it understood the need to be absolutely squeaky clean in this new industry and they were up for that," Reti said.
"The Greens have listened to one version of the pleadings from East Coast-based Hikurangi Enterprises (which has a licence for medicinal cannabis) and ignored the rest of the industry, who were completely behind the fit-and-proper-persons requirements."
He called the Greens "soft on drugs" but Swarbrick, the Green Party's spokeswoman for drug law reform, dismissed this as "classic National Party hysteria".
"If you're convicted of something while it is illegal, you serve your time," Swarbrick told the Herald.
"If that substance then becomes legal and regulated and you jump through the same hoops that everyone else does, why shouldn't you equitably be able to engage in that market?"
The people who have been disproportionately penalised by the war on drugs shouldn't be excluded from participating in a legal market, she said.
She had visited Hikurangi and spoken with people taking a course at the Eastern Institute of Technology's Ruatoria Regional Learning Centre on experimental hemp production.
"Some of them have gone away for that substance and have served their time and are now they're looking to use their skills and invest in their community. And this is a massive economic opportunity for them."
It was Green Party policy to have regard for equity and social justice in drug law reform, but she said it was not yet party policy to allow those with previous cannabis convictions to work in the medicinal cannabis market.
"I guarantee we will have discussions on that point [during the Government's public consultation process] and it's something that should be discussed with maturity."
Currently, licences for medicinal cannabis are only issued for medical or scientific research.
The Government's medicinal cannabis law was passed last month and the regulatory framework, such as rules around licences and quality standards, will be drawn up after public consultation.
A binding referendum on legalising cannabis for personal use will take place at the 2020 election.
Canada's legal cannabis regime started in October last year and includes a pardon for convictions for carrying 30g or less of marijuana, but not for other crimes such as supplying cannabis.
The Canadian Government has been criticised for not expunging cannabis convictions, which would remove any record of a criminal conviction; a pardon seals the record but does not erase it.