A bank economist is predicting New Zealand's landlords will spend billions of dollars upgrading their commercial buildings to earthquake-proof standards next year.
BNZ head of research Stephen Topliss says many buildings around the country need to be quake-proofed and the cost of that exercise is being underestimated.
Listed landlord Kiwi Income Property Trust recently announced that it will cost $35 million, or about a third of the building's value, to strengthen the Majestic Centre in Wellington against earthquake.
Mr Topliss says all listed property companies will be going through their portfolios deciding what complies and what doesn't.
However, he says those companies are probably buying at the top end of the market and so are less vulnerable.
"The people who are probably most vulnerable are the people I guess with less money who have gone into little consortia and bought little wee buildings all over the place who are going to get a big shock when they find out what they actually have to do.
The expenditure needed, he says, will be a "double-edged sword" for the economy.
While the increased construction activity will help drive economic growth, those paying for the work will feel the pressure in increased costs of doing business - a negative for the economy.