Auckland Council is paying $104 million for the current headquarters of ASB Bank.
The 35-level Albert Street building will become the council's new headquarters when the ASB moves to new premises on the waterfront in a year.
The council will empty its existing, much smaller, civic administration building and exit two leased downtown buildings a year later.
Chief executive Doug McKay says finding a building that can house 2400 personnel, so close to the Town Hall and Aotea Square is a good deal.
He says the council has not yet looked at how, or whether, the building might connect to Aotea station on the proposed downtown rail tunnel.