The New Zealand sharemarket has followed major markets in the US and Europe lower.
The benchmark NZX50 index is down about 100 points or 0.8 percent in the first hour of trading to sit at a three-week low.
Most stocks have fallen, with some of the biggest declines among technology companies.
The fall is the biggest in two months and followed big falls on overseas markets overnight amid concerns that rising Covid-19 cases might derail economic recovery.
All three major U.S. stock indexes ended sharply lower, between 1 and 2 percent. The S&P 500 and the Nasdaq suffered their largest one-day percentage falls since mid-May.
European markets were about 2.5 percent lower.
"The markets suffered a summer swoon today with Covid fears again at the forefront of investors' minds," Chris Zaccarelli, chief investment officer for Independent Advisor Alliance said.
The New Zealand sharemarket has been underperforming most overseas exchanges, which have been posting strong rises and records fuelled by large amounts of cheap money looking for stronger market returns.
- RNZ / Reuters