Tweets that weren't so favourable of cannabis argued it carried mental health risks and caused physical problems like "bong lung".
One person wrote: "Wellington absolutely reeks of weed. It is disgusting."
The researchers, from La Trobe, Otago, Auckland, Sydney, Brown and Miami universities, said the study aimed to gauge the views and opinions of Kiwis, via tweets.
They used a Twitter-sponsored commercial platform to access all cannabis-related tweets dating back to July 2009, and found some 304,760 of them.
Next, they used machine-learning to code the sentiment of the tweets, sorting them as positive or pro-cannabis, negative or anti-cannabis, or neutral.
An example of a "neutral" tweet was: "I feel like everything smells a little like weed at the moment."
Overall, they found the tweets were predominantly positive - 62 per cent - and there was a also higher proportion of these "pro-cannabis" tweets written in 2020 (65.3 per cent) compared to negative or neutral tweets.
For those tweets that specifically related to the referendum, the data showed a generally positive (53.5 per cent) view of cannabis.
"Both cannabis-related, and referendum-specific tweets, suggest that Twitter users in New Zealand have a generally positive view of cannabis," the study authors wrote.
"Given the nature of Twitter, the current method will allow us to study whether views toward cannabis change as the referendum nears and capture any late swings in pro- or anti-cannabis sentiment."
But the researchers added that one limitation was that they could not get demographic data from Twitter, so their sample was likely to be younger and more educated than the general population.
The study comes as a new poll suggests voters might be narrowly leaning towards a yes vote.
The poll, released by the Helen Clark Foundation and the New Zealand Drug Foundation, showed 49 per cent of respondents support the legislation, while 45 per cent oppose it.
When those who responded "unsure" were asked which way they were leaning, a further 2 per cent leaned in favour of voting for legalising recreational use of cannabis.
But the results differ with a recent Colmar Brunton poll, released on September 26, which showed support for the legislation was going up in smoke.
What NZ Twitter thinks of weed
Positive
• "Smoke weed everyday."
• "Marijuana helps me with my depression and I sleep so much better after hitting the blunt."
• "I love going to bed stoned and feeling good first thing in the morning."
• "Want to protect young kiwis? Best thing to do is vote YES in the cannabis referendum! #voteyes."
Negative
• "Ew no. I do not smoke weed. Never have, never will."
• "Finally giving up the weed. Feel so much more productive already #saynopetodope."
• "Wellington absolutely reeks of weed. It is disgusting."
• "Vote no in the upcoming cannabis referendum. It is not worth the harm and the impact it will have on young NZers."
Neutral
• "Cannabis consists of a variety of different compounds called Cannabinoids."
• "I feel like everything smells a little like weed at the moment."