tdgeek:
Vacant Houses? If they stay vacant then there is no effect. If I had a vacant house, I paid for it, thats my business
If they are vacant and could be lived in, then they are already having an effect. Just because someone owns a vacant house, doesn't mean that Government can't tax you on it. I think they do it in places in Australia, and they have this tax around the world, as a way to either get people living in the house, or to get the owner to sell it so it can be lived in. Apparently it has helped a lot to increase housing supply.. Land tax also would help get landbanked sections built on.
NZ needs to make the best use of it's current resources and existing housing stock.
Already taxpayers are having to pay increasing amount for emergency housing, when there are vacant houses that could be used. Child poverty in NZ is also suffering as a direct result.