ANZ's Truckometer indicator is pointing to a tepid start to the year and a risk of recent history repeating, where short-term surges in momentum are followed by a slump, ANZ economist Sharon Zollner says.

The heavy traffic index reflects truck movements on 11 roads selected because historically they are a good fit with economic activity at the time.

It rose just 0.3 per cent last month to be 0.4 per cent below the average monthly reading during the December 2012 quarter.

The heavy traffic index suggests that a solid out-turn when the December quarter gross domestic product is reported next week - ANZ is forecasting a 0.9 per cent rise - could be followed by a weak, or even negative, March quarter, unless traffic picks up a lot this month, Zollner said.


When monthly volatility is smoothed out by taking a six-month rolling average, the heavy traffic index is still pointing firmly downhill for growth momentum.

Meanwhile, the light traffic index - tracking movements of cars and vans on nine roads chosen to give a six-month lead on GDP growth - fell 1.6 per cent last month, unwinding its rise in January.

"The trend in this index has now turned negative, suggesting a lack of economic momentum mid-year," Zollner said.

"Rapidly worsening drought conditions on top of stop-start economic momentum add up to a potential pothole in 2013 that some would characterise as a recession."

Zollner stressed that ANZ is not forecasting such a pothole.

"We're picking something more akin to anaemic growth, but the job of the Truckometer is to raise red flags before other indicators do," she said.

"We still have the Canterbury rebuild, but when you add in the drought and a tightening of fiscal policy, the rebuild might be a bit out-voted."