An economist says slowing activity in the services sector could indicate that overall growth is stalling.
The BNZ-Business New Zealand performance of services index eased more than 2 points to a seasonally-adjusted 50 in August, its fourth consecutive monthly fall.
A reading at 50 indicates that the sector is neither expanding nor contracting.
BNZ is expecting a slight decline in June gross domestic product figures on Thursday, but is forecasting the economy will grow 0.7% in the three months to September.
Senior economist Craig Ebert says figures are volatile month to month, and it is hard to pick trends.
Last week, manufacturing activity contracted.
The GDP-weighted composite index, which combines the manufacturing and services surveys, fell two points to 49.6, the lowest level since July last year.
