Electronic retail card spending has fallen for the first time in three months, due to a decline in spending on big ticket items, and food and drink.
Debit, credit and charge cards fell a seasonally adjusted 0.8% in May, Statistics New Zealand says.
Retail spending has been sluggish because people have been focused on repaying debt, though some economists say there is now evidence that consumer caution is starting to ease.
The data covers about two-thirds of retail sales, and does not include cash and cheque transactions.
Overall, transactions remained flat, falling slightly by just 0.1%.
ASB analyst Christina Leung says spending in the services area increased and, overall, a gradual recovery in retain spending is occurring.
She says part of the decline in May was due to lower diesel and petrol prices, while the weaker spending on clothing may be due to the milder autumn weather.
Ms Leung expects retail spending will be boosted by the Rugby World Cup later this year.
The figures include card transactions in Christchurch, although Statistics New Zealand says it is not able to estimate the effect of the Canterbury earthquakes because figures are not broken down by region.
However, the agency says retail spending has been sluggish over the past year as consumers pay back debt instead of spending.
It also says people have been cautious in the face of weak wage growth, high unemployment and the rise in GST.