I don't think you understand the NZ situation very well; the government collects very little from property sales compared to most parts of the world, because there's no stamp duty and there's practically no capital gains tax.

That said, government revenue isn't even the problem, the excessive cost of housing is the problem.

The government is already interfering in the housing market by not taxing it at the same level as normal income; by making it tax advantageous to earn capital gains rather than by labour it pushes money into that market.

I'd prefer that they stopped messing with the housing market by treating it the same.