The latest BNZ-Business New Zealand performance of manufacturing index stood at 53.3 in June.
A reading above 50 indicates expansion.
Manufacturing activity has now expanded for the 21st successive month, led by production.
But the pace of growth has eased, with new orders at the lowest level since the end of 2012.
Executive director of Manufacturing New Zealand Catherine Beard said although still in expansion territory, manufacturing was easing back - particularly new orders.
Ms Beard said it's encouraging most firms are continuing to take on staff, indicating activity should remain healthy in coming months.