WELLINGTON, New Zealand — New Zealand is known for its tourism campaigns emphasizing what a clean, green country it is, and after 2020 it might be even greener: A referendum will be held that year on whether recreational cannabis use should be legal, the justice minister said on Wednesday.

It appears that New Zealand would be the first country to put the issue to a nationwide vote.

Andrew Little, the justice minister, said the referendum would be on the ballot during the next national election, due to be held in 2020. He told reporters that the results would be binding, though he said there was still “a bit of detail still to work through,” particularly regarding how the question would be worded.

The announcement came a week after New Zealand’s Parliament passed a law that will ease restrictions on medicinal marijuana.

Public opinion in New Zealand has become more supportive of recreational cannabis use in recent years; an October poll by 1 News found that 46 percent of those questioned favored legalizing the drug, while 41 percent were against. The poll questioned 1,006 eligible voters and had a margin-of-sampling error of 3.1 percent.