The Labour-led Government will act on making medical cannabis more accessible next week.

But instead of supporting an existing Bill in the House, the Government will introduce its own legislation.

Labour campaigned on making medicinal cannabis available for people with terminal illness or in chronic pain, promising to introduce the legislation within its first 100 days in Government.

The Bill currently in the House is in the name of Green MP Chloe Swarbrick. She took over stewardship the Bill from Julie Anne Genter, because member's Bills cannot be tabled by Ministers.

The Greens Bill would make it legal for people suffering a terminal illness or debilitating condition "to use cannabis or cannabis products with the support of a registered medical practitioner".

It would also allow people with terminal illness to grow their own cannabis - which may have been a step too far for Labour and coalition partner NZ First.

Ross Bell of the New Zealand Drug Foundation says he's not surprised Labour is introducing its own legislation, rather than adopting the Greens Bill.

"I think there's almost a bit of discomfort within Labour around some of the effects in the Greens Bill, including the ability to grow their own," he told Newshub.

"I think that's partly around the sensitivity around their coalition partner, New Zealand First."

He said Winston Peters made it clear to the NZ Drug Foundation that he doesn't think people should be able to grow their own medicine.

Mr Bell said doctors could be reluctant to prescribe raw plants, and making it easier to import cannabis product from Canada and the Netherlands would be an important step.

He said it was unlikely the Bill will go as far as to allow compassionate access, directing police to turn a blind eye to people on a list of medical cannabis users.

But he said Labour is the party of trade unionist Helen Kelly, who fought to allow access to cannabis for medical reasons.

The Greens were promised a referendum on the recreational use of cannabis as part of its confidence-and-supply agreement with Labour.

It will take place at or before the 2020 election.

Newshub.