Residents are being advised to stay indoors after a chemical spill in Motueka, near Nelson.
Police said a quantity of hydrogen cynamide leaked from a barrel on the back of a truck and on to a road.
The chemical can kill if swallowed, inhaled or absorbed through the skin, or can cause severe skin and eye irritation.
Police are advising people to avoid the corner of High St and Tudor St while emergency services clean up the spill. Nearby residents have been advised to stay indoors and keep their windows shut.
Fire, police and ambulance services are at the site and contractors have been called in to clear up the spill.
Hydrogen cynamide, more commonly known as Hi-Cane, is often sprayed on kiwifruit vines.
