HBF will own, occupy and sub-let the 10-storey building, which will be one of seven towers ultimately constructed at Kings Square.
Construction on the first three towers at Kings Square has already begun, led by Leighton Holdings subsidiary Broad Construction, with anchor tenants Shell Australia, DEXUS Property Group and John Holland lined up to take up space in the buildings.
Mr Day said the precinct was expected to attract around $1 billion in private sector investment.
The land was opened for development by the sinking of the Perth to Fremantle rail line under the Perth City Link, Mr Day said.
“The sinking of the rail line is the first step in the transformation of the CBD,” Mr Day said in a statement.
“It opens the way for the offices, apartments, shops, community spaces, restaurants, cafes, a child care centre and gym that will follow.”
The first four towers at Kings Square are expected to be complete by mid-2015.
Mr Day said the next phase of major works for the Perth City Link would begin early next year, with the completion of rail works.
Construction of the underground bus station will begin once the rail component is complete, he said.