Simon Bridges believes an upcoming referendum on the personal use of cannabis could be New Zealand's own version of Brexit.
Justice Minister Andrew Little announced in December a referendum on the drug will be held at the 2020 election, and it will be binding.
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The Green Party got an agreement to hold the referendum as part of its confidence and supply negotiations with Labour.
There is yet to be an announcement on what question will be asked and it's not yet known what the detail of any proposed law change would be.
Mr Bridges told The AM Show he's most likely to vote no, but wants to see what he's up against.
"We've got so little detail, so little meat on the bones I think we need to see.
"That's the work Paula Bennett's going to do, working out what is the legislation that would go with it, how will it affect police, what will it mean for methamphetamine, all of these things."
He compared the current lack of clarity to Brexit, referring to the current crisis as the UK moves to formally exit the European Union without any plan.
The NHS is currently stockpiling medicines and supermarkets are stockpiling tinned food due to fears of the fallout from leaving the EU.
Mr Bridges said New Zealand could also be in for trouble if it votes without an idea of what the end result would be.
"Take the example of Brexit, let's not have a vote and not know what the detail is going to be until afterwards," he said.
"Let's work it out before, so we all know exactly what we're up for and what we're voting on."