New Zealand manufacturing activity improved again last month, with all regions expanding, though economists warned a stronger kiwi dollar could weigh on the sector's export earnings.

The BNZ-BusinessNZ performance of manufacturing index rose to a seasonally adjusted 57.7 from 57.2 in May. A reading of 50 separates expansion from contraction.

The sector has grown nearly every month since October 2012 and has held above its 53.1 long-term average for the past 12 months.

Four of the five PMI sub-indices rose in June. New orders rose to 61.6 from 60.1, deliveries to 56.2 from 55.3, finished stocks to 50.9 from 49.4 and jobs to 53.5 from 53.1. Production fell to 60.8 from 61.2.