Building work boomed in the March quarter, led by home building in Canterbury.
Total home building was up 15 per cent in the quarter, compared with a surprisingly weak 2.3 per cent lift in the December quarter, Statistics New Zealand figures show.
The 15 per cent lift was the highest quarterly increase since September 2002, when it rose 16 per cent.
Overall, home building and non-residential building work was up 16 per cent - far higher than forecast.
Westpac Bank economists had expected total building growth of about 5 per cent, with the stronger than expected gains shared across the country, while Canterbury was up 25 per cent by value.
With more work expected in Canterbury and in other parts of the country, the building boom looks set to beat that of a decade ago.
Westpac said the latest construction figures suggested total economic growth could be greater than its 1.1 per cent forecast for the March quarter.
UBS senior economist Robin Clements said it was an "understatement to say this [16 per cent jump] is a big upside surprise".
As the construction sector was about 5 per cent of the total economy, the latest building figures could add three-quarters of a percentage point to March quarter growth.
The trend for residential building work has been rising for 10 quarters in a row and is now 62 per cent higher than the most recent trough in the September 2011 quarter.
However, it is still 10 per cent lower than the series peak in the June 2004 quarter.
Non-residential building work volumes were up a seasonally adjusted 17 per cent.
Overall, building activity was up 16 per cent in the three months, Statistics New Zealand said.
These figures are for work carried out, rather than forward-looking building consents, which may or may not be completed.
The building activity figures had lagged behind the pipeline of consent figures so had been expected to catch up at some stage.
"The trend for all building activity is rising, but the current level is still 5.6 per cent lower than the series maximum in the June 2005 quarter," Statistics New Zealand business indicators manager Neil Kelly said.
In current prices, the unadjusted value of all building activity in the March quarter was $3.5 billion, comprising $2.2b of residential building work and $1.3b of non-residential building work.
All building activity in the quarter was higher across all areas of New Zealand compared with the March 2013 quarter.
Total building activity in Canterbury, in current prices, increased a seasonally adjusted 25 per cent in the March 2014 quarter after a 3.8 per cent increase in the previous quarter.
Residential building was up 31 per cent in Canterbury compared with a 12 per cent gain in the rest of the country, and non-residential work in Canterbury was up 16 per cent compared with a 19 per cent lift in the rest of the country.
Building activity figures from Statistics New Zealand show that more than half a billion dollars, or $578,211,000, was spent on new house building in the region in January, February and March.
The figures follow last week's consent data which showed council approvals for new houses and apartments in Canterbury was the highest since electronic records began in 1990.
The information also reveals more is now being spent on house building than non-residential building in the region.
Construction of commercial, public and other non-residential projects was $336,382,000 in the first quarter, rising 16 per cent since the previous quarter, compared with 19 per cent nationally.
Government Statistician Liz MacPherson said construction across the country has been increasing for 2 1/2 years.
The figures show all Canterbury building activity had doubled since mid-2010, before the first of the earthquakes hit the region.
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