Green Party MP Chloe Swarbrick's Member's Bill will be voted on in Parliament on Wednesday, but will it get over the line?
Ms Swarbrick told The AM Show she and the Bill's supporters would just "have to wait and see" whether the conscience vote will get a majority.
She said recent developments had made things "really interesting" over the past 24 hours.
"We've obviously had Bill English come out and say it's not quite a conscience vote for the National Party caucus," she explained.
"I'm a bit confused by that, as this issue is about people who are in pain and suffering, those with chronic pain or multiple sclerosis and others who could benefit from the use of medicinal cannabis who are currently having it denied."
Ms Swarbrick says at the moment, people who want to be able to use medicinal cannabis are "jumping through hoops with the Ministry of Health".
For many countries, she says, growing your own cannabis for medical purposes is "pretty much in the mainstream" and makes it far more affordable for people.
For those cleared to use the usual prescribed medicinal marijuana product, Sativex - a group of less than 100 Kiwis - it comes at an expense of about $1000 every month.
And these people, who could seek illegal means of getting cannabis for a fraction of the price, would be identified as criminals just for taking the matter of pain relief into their own hands.
"[Kiwi trade unionist] Helen Kelly's name has been brought up a lot - under the Government's Bill, she would have been criminalised in her final days," she said.
"We're really late to the game. For a country that prides itself on caring for each other, we are really slow off the mark when it comes to reform around medicinal cannabis.
"If we look at international jurisdictions around the world, and where our medicinal cannabis reform would be heading, we would be sitting at the most conservative, constrictive end internationally."