Also should add there are ducted air heating options for gas, similar to a ducted heatpump that are cheaper to install than a radiator or underfloor heating hydronic systems.
The hydronic systems will save you that annoying noise and draught from pushing all the air around though.
And my comment about running costs being the same as a heatpump, that is for mains gas. LPG runnings costs are a bit higher.
And who says you can't install a woodfire in Auckland? Just saw the new bylaw has come into effect, which doesnt seem to ban them, just requires cleaner burning models? 
All in all many great options for heating that avoid drawing electricity during peak periods.
 e.g. http://www.bonaire.co.nz/