ANZ's Truckometer indicator is pointing to an economy with a lot of momentum.

The heavy traffic index eased 0.9 per cent last month, but the September quarter as a whole has recorded the strongest quarterly increase in its 13-year history.

"It suggests a potentially spectacular September quarter GDP result," said ANZ economist Sharon Zollner.

The heavy traffic index tracks trucks on 11 roads that have historically matched the economic output at the time.


The index has shown a steep upwards trend in the past six months. The Truckometer, released yesterday, also has a light traffic index, which tracks cars and vans, and which provides a pointer to activity six months ahead.

It fell 0.4 per cent last month to complete a fairly ho-hum quarter, Zollner said.

The light traffic index predicted solid GDP growth for the remainder of the year, averaging a robust 3.5 per cent annual pace. After such a surge a period of consolidation in the new year would not be unreasonable, she said.

Overall the indexes suggested the economy would truck on through the second half of this year with a very strong dairy payout and a hefty pipeline of construction work underwriting the near-term outlook.

"In the longer term, our concern is that the economy simply does not have the resources to facilitate a construction boom and a consumption boom at the same time. Something will have to give," Zollner said. "But for now, New Zealand is on a roll."