So, go convince your local Clueless Council not to do the two things that have done most to make houses unaffordable:
1 - draw zoning squiggles on planning maps, thereby ensuring a 10 times raw land price differential between one side of the fence (rural, no builds) and t'other (urban, build away). The difference is pocketed by the lucky land-owner, and guess who pays? Right, the eventual house/section buyer.
2 - levy development taxes on every section/house. Mike Greer, here in Christchurch, estimates direct Council costs as $75K per house/land sale. Guess who pays. Right, you, the house/land buyer, and with oncosts, interest, developers margin on top.
Of course, banks just love increased costs, too, but they aren't the ones who set this whole dreadful ratchet effect in motion.
The Economically Clueless Councils did.
There. Fix these two things, get Affordable houses.
Easy, weren't it?