New Zealand's traffic volumes rose 3.3 percent in May as warmer weather and late-season dairy production lifted demand, according to ANZ New Zealand's Truckometer.
The survey uses traffic volumes as an economic indicator of gross domestic product. Light traffic volumes fewer than 3.5 tonnes, rose 2.7 percent and heavy traffic volumes, increased by 7.5 percent.
"I would be pretty convinced we are seeing record volumes of dairy," said Ken Harris, director of transport logistics company NZL Group. "We have had quite a strong six months - I'd say we are tracking a little ahead of where the survey is. As a whole transport companies have been at capacity across the board."
Of the 21 traffic series used in the survey, 12 rose by 3 percent or more in seasonally adjusted terms, with eight located on major transport routes to and from dairy factories.
"Autumn dairy production is estimated to be at least 35 percent higher than its 4-year average," said Sharon Zollner, economist at ANZ. "We expect that while some of this large jump may well be "noise", much of it is a real economic signal - but one that refers to quarter two, rather than quarter four, as the Truckometer's lead would normal imply."
Heavy traffic volumes have the closest fit to GDPs.
"If it simply reflects that the weather in May was far more summery than usual and this caused people to head off in those weekend trips that they had postponed, then the implications for GDP are limited," Zollner said. "The result may be weather-affected rather than reflecting economic momentum."