Propelled by good growing conditions on the farm and a pick-up in quake-related construction, economic activity grew 0.6 per cent in the June quarter, beating market and Reserve Bank expectations.
Agricultural output grew 4.7 per cent to record levels, with higher milk production the main contributor, Statistics NZ said.
Over the year ended June agricultural output was up 6 per cent on the year before - three times the growth rate of the overall economy.
"Although this boost is encouraging, it is not expected to last," said Infometrics economist Matt Nolan. "Eventually growing conditions will return to normal and agricultural production will decline from its current peaks."
By contrast, construction's 3.3 per cent growth in the quarter is seen as just the beginning.