A report from the US Institute of Supply Management (ISM) showed America's manufacturing sector contracted for the second month in a row in September to its lowest point since June, 2009.
The ISM index used to be called the NAPM Survey, which traders nicknamed the "napalm" because of its ability to move markets.
Markets globally have been sharply lower this week as worries about a world economic slowdown start to bite.
In the UK, the share market's FTSE 100 closed more than 3 per cent lower, the largest one day fall since January 2016 and exceeding the decline that followed the UK referendum in June 2016.
Harbour Asset Management portfolio manager Shane Solly said the US decline was driven by weakness in the energy, materials and financial sectors.
"We don't have a big exposure to those sectors here in the New Zealand market but we will get hit by some of the weakness in this whole global meltdown," he said.
Solly said October typically can be volatile due to holidays in various parts of the world coinciding with the release of key economic data.
"It has a history of being a bumpy month."
While the New Zealand share market has been weak in recent days, it has had a phenomenal run.
At today's level, the S&P/NZX50 Index is still more than 2000 points or 25 per cent higher than where it started the year.