The economy is gaining momentum but still faces obstacles such as interest rate hikes, an economist says.
ANZ Bank's Truckometer measures traffic flows on certain roads and calculates the economic impact.
The heavy traffic index, an indicator of the economy right now, rose 2.3 percent last month, while the light traffic index, which predicts growth six months ahead, fell 0.4 percent.
ANZ economist Sharon Zollner said both series had strong upward trends, which boded well for the economy. However, there were always headwinds to an economy.
"At the moment, there's a couple of obvious ones. The New Zealand dollar is still extremely strong - has been for some time - and now interest rates are widely expected to be lifted on Thursday this week," Ms Zollner said.
"That's the first time in many years that we've had an interest rate hike, and I think it will come as a bit of a surprise to some, even thought it's been well flagged by the Reserve Bank. That will put a bit of a brake on some things."
As well, the global economic picture was looking full of risk, she said. Commodity prices were high and had doubled but could just as easily halve as they could be volatile.