ANZ says its Truckometer indices suggest the economy is settling in for a sustained period of growth at least until the middle of the year.
The heavy traffic index rose a seasonally adjusted 2.3 per cent last month, following a flat January.
The index tracks truck movements on 11 roads chosen because of a good fit historically with gross domestic product at the time.
"The upward trend in the index is steep," ANZ economist Sharon Zollner said, "and is indicating acceleration in annual GDP growth - in agreement with robust business and consumer confidence."
The light traffic index eased by 0.4 per cent last month, reversing its rise in January. This index does not have such a reliable relationship with the level of GDP but has done a pretty good job of picking the ebbs and flows of growth six months ahead over recent years, Zollner said.
Last month's fall should be seen in the context of a string of predominantly strong out-turns.
"These have resulted in the most sustained implied quarterly growth profile since the bounce out of recession in 2009-10. However ... the light traffic index suggests the September 2013 quarter may have been the peak in quarterly growth."
Both series had solid upwards trends boding well for a continuation of momentum into the middle of the year, she said.