from 2010 rawlinsons: dont use this too accurately as im no expert. better off using your own resources, 2012 building price index not accounted for
excludes demo and all site considerastions

Ground Floor:
Entrance and office space. 1650-$1780/m2
back of that would be storage and bike stands,waste room. no CAR PARK REQUIRED. maybe $600/m2 for this

First to Fourth Floor:
26 Apartments -1805-1950/m2 med-std finish, (price for up to 3 floors, so treat with caution) no lifts/balconys considered

Also

Roof top Garden: unsure of this ?? 600 maybe. lots of considerations though

lifts to roof top: 90k (2 floors) + 9.5k each extra floor

around 9 Solar hot water panels on roof. not sure

go see a quantity surveyor, they’ll have historical data for ur area for a more accurate sqm cost rates. and also provide information on the design on the building so that life cycle costing is considered

1st post but the quickest was would be using ‘rawlinsons’ as a cost guide for pretty much any construction costs.
probably as accurate as youll need for conceptual investments