New Zealand's manufacturing sector contracted even further last month, showing its worst jobs rating in more than three years, according to the latest performance of manufacturing index (PMI).

The BNZ-Business New Zealand PMI for August was 47.2 on a scale where a reading above 50 indicates expansion and below 50 contraction, which was 2.2 points down from July and the lowest level of activity since November last year.

In the last three months, the PMI had averaged 48.6, said a statement from Business New Zealand.

The August result was obviously not in the right direction in terms of growing the sector, although other manufacturing information releases showed the overall picture to be complex, Business New Zealand executive director for manufacturing Catherine Beard said in the statement.

"The recently released Statistics New Zealand Economic Survey of Manufacturing showed that despite dips in particular areas of manufacturing, such as simple commodity-based products, the other end of the manufacturing scene involving elaborately transformed manufactured goods have done well over recent months with boost in both values and volumes. In addition, some of the sluggish demand has been due to cyclical movements of commodity products," she said.

BNZ economist Doug Steel said international concerns, including further signs of slowdown in China and Australia, were one likely reason behind the August result.

"The strong New Zealand dollar is also a major drag on local manufacturers. The fact that New Zealand's PMI is generally in line with international comparators will bring little solace to local manufacturers, but it does add some context," he said in the statement.

All five sub-indices were in contraction in August for the first time since October 2011, with employment faring worst on 45. 4, down 2.1 points from July and the lowest result since July 2009.

Production was down 1.9 points to 47.6, while new orders and deliveries were both on 48.1, and finished stocks was the only sub- index to improve, rising 0.4 points to 48.