Howdie, some dependencies
location
slope of land and earthworks
soil test and impact on footings
council requirements for offstreet parking, water tanks etc.
architectural style and variation from a simple structure
living area m2, patios pergolas, eaves
quality of fixtures and appliances, air con,remote garage doors, roof insulation
whether you want a turnkey solution providing turf, landscaping, drives, clothesline, tele antennae.
I factor on $800-900m2 for basic turnkey lowset brick veneer homes on the outskirts of Brisbane.
I'd guess you might pay around $1200-1500m2 for an uncomplicated basic spec townhouse construction, based on my talks with builders. 2 storey buildings are more expensive m2 than single. plus you need a proper DA and all the consultants that go with that. block, render, and hardiplank all add expense above brick veneer.
Some other stuff
aggregate drives $60-70m2
turf delivered $3m2
fences $40-50/m
water tanks...just remember you may not be entitled to rebates if it is compulsory to put tanks in. depends on your local council