Lynne Ray, manager of NZ Moray Property Ltd, which owns the building, said, when contacted, yesterday that depending on the weather, scaffolding would be removed within about three weeks and some final work, including the capping of mullions (vertical window divides) and installing of more windows, would be completed in coming weeks.
European-owned Moray Property gained resource consent in October 2004.
The three-storey extension takes Otago House to 42.5m above ground level - about 13.5m lower than neighbouring First Church's spire.
The project has so far gone to schedule and now a new floor was being built on the 11th storey, which used to be the rooftop.
External construction was due to be completed by the end of March, by which time internal fit-outs would be under way, but a final completion date had not been set, Ms Ray said.
The three storeys, which total about 3000sq m of space, would be occupied by existing tenants, leaving about two floors available for new tenants.
Ms Ray said there had been some interest in the space.