Engineers have begun checking buildings in the three largest cities for the sorts of weaknesses found in the collapsed CTV building in Christchurch.
One-hundred-and-fifteen people died when that building collapsed in the February earthquake last year.
The main fault was columns that lacked reinforcing steel - which were permitted in some buildings put up between 1982 and 1995.
The Department of Building and Housing says it is now checking about 350 multi-storey buildings built between those years in Auckland, Wellington and Christchurch.
Chief executive Katrina Bach says that will be completed by late April or early May this year.
Ms Bach says they will check multi-storey buildings throughout the rest of the country once this stage is complete.