The Green Party's wealth tax idea is nuts.

I'm surprised the Prime Minister hasn't killed the idea immediately, and I'll get to that in a minute.

But first, how on earth did the Greens decide that someone earning $100,000 a year or someone sitting on a $1 million property is rich?


To put that in context, the average wage in this country is $77,000. Auckland's median house price is $875,000.

So what the Greens consider rich is actually not rich at all - more like just managing to do marginally better than average.

And it's nuts to start hiking up taxes on average, middle New Zealanders at a time when the economy needs to be encouraged to rebuild.

And this is why I'm surprised Jacinda Ardern hasn't ruled it out immediately.

Because tax – especially tax that seems unfair - is a vote killer.

This is going to chase away voters.

It's not going to chase away Green Party voters. They're going to love a policy that takes money away from "rich" baby boomers and gives it to students and beneficiaries.

This is going to chase away centrist Labour voters, because it's going to remind them how nutty the Greens can be and what a Green-Labour coalition might well get up to if there's no New Zealand First in there to rein them in


And remember, that is the most likely combo for government right now: Labour plus the Greens and no one else.

Winston's party's at 2 per cent. They're not looking good for getting back into government. Until now maybe, because there's a good chance those nervous centrist Labour voters start considering NZ First as an option again just to avoid the loopiness that might ensue from a red-green combo.

Labour clearly hasn't learned from the capital gains tax fiasco last election. Remember how that played out? As soon as the PM promised a CGT, her polls started falling.

This time, it might not be her policy, but if it's coming from a party she is most likely going to need, it's close enough for some voters.

Unless she rules this out, there is the risk that this becomes capital gains tax 2.0.