Do you have sources regarding the "left's irrational opposition to nuclear power"?
I guess it's a manner of perspective.
A couple of interesting facts: 1) the galvanising moment for this was the “Rainbow Warrior affair” in which French intelligence agents were caught after having sunk the Greenpeace vessel of the same name; 2) the nuclear-free zone act does not prohibit use of nuclear generation in NZ.
Specifically it doesn’t prohibit all power generation, but it does prohibit nuclear propulsion. Which again has no impact outside of irritating allies, as NZ never has had and never will have a use case for commercial nuclear power production. It’s a very small country, and 80% of its electricity is already renewable.