Economic growth looks to have improved in Q4 but the start to 2013 is not particularly promising, according to the latest ANZ Truckometer indexes.
The Truckometer analyses data from the movements of light and heavy vehicles, using the results to predict economic activity.
Heavy vehicle traffic tends to be an indicator of current economic activity, while flow for cars indicates future growth or decline.
Both indexes rose in January, the heavy traffic index by 2.5% and light traffic by 1.7%.
The report says based on the heavy traffic index, it is expecting GDP growth of 0.8% for Q4.
However, despite the bounce back from a drop in December, the start to Q1 is not so promising.
"The underlying picture according to this indicator remains one of softness across the economy."
A lift in the light traffic index, however, is more encouraging.
"If this continues, it would suggest things may start to look sustainably better from the middle of the year.
"However, we will require some more convincing before we get too excited – one poor month could break the fragile upward trend at this point," the report says.
"Putting it all together, the message from the Truckometer indexes is for a continuation of bumpy, tepid economic growth into the middle of this year.
"The big hope is the Christchurch rebuild effort, which will largely not be captured in these indicators, but which is expected to really kick into gear in 2013.
"It could prove to be a well-time stimulus."
The report says the Truckometer will not reflect the rebuild effort directly, but the indexes will show how the effects of the rebuild feed into the wider economy.