"If the Housing Accord is successful in delivering 39,000 homes and sections, we estimate it will result in an oversupply of 10,000 homes. A significant increase in the housing supply, alongside the Reserve Bank's efforts to cool highly geared credit growth, is a significant risk for house prices in Auckland," NZIER principal economist Shamubeel Eaqub said.
A sharp pick-up in building activity, not only in Canterbury but in Auckland, is a key factor underpinning NZIER's forecast of 3 per cent economic growth next year - the strongest since 2007.
While that is in line with the consensus among other forecasters, NZIER is taking a contrarian view on the outlook for interest rates.
Eaqub said the Reserve Bank would be loath to raise interest rates until the economy was on a stronger footing, jobs were more plentiful and inflation was picking up. He expects those conditions to be met by March next year. However, they are necessary conditions but not sufficient.
Interest rate hikes would also be contingent on the success of the Reserve Bank's curbs on low deposit mortgage lending, he said, which by March next year would have been in place for six months, long enough to assess their efficacy.
If successful, the Reserve Bank would hold the official cash rate steady at 2.5 per cent until the end of next year. If not it would raise interest rates quickly from next March.
"We reckon the first will be a 50 basis points hike, to send a warning shot," Eaqub said. The Reserve Bank has been coy about saying what would constitute success.