Emergency services are at the scene of a potentially serious chemical spill in Riverlands.
An ammonia leak on Liverpool Street in the industrial estate just outside Blenheim has seen the area closed off.
A cordon is being put in place with the area out of bounds to the public while fire crews work to contain the leak and the road is blocked off to traffic.
Police are also at the scene.
A Fire and Emergency New Zealand spokesman says the alarm was raised shortly after 11am.
"The spill is contained and the scene is isolated," the spokesman says.
"The safety aspect is good."
He says there are no injuries.
Exposure to high concentrations of ammonia in air causes immediate burning of the eyes, nose, throat and respiratory tract while lower levels can cause coughing, and nose and throat irritation.