So, the Greens are making a serious push to win Mount Albert by standing co-leader Russel Norman as their by-election candidate. I'm expecting a tidal wave of Labour outrage at the thought of another left-wing party standing in "their" seat, but I have just two words to say in response: "screw them". Seats don't belong to parties - they belong to the voters who live in them. And if Labour wants to win that seat, they should have to fight for it against whoever puts their name forward.
If they're that concerned about "vote splitting", then here's a suggestion: rather than seeking to limit voter choice, they could enhance it by pushing for preferential voting in the electorate vote.