The Fire Service has set up cordons and is using hazmat gear to clean up an 800-litre chemical spill near Timaru.
Emergency services were called to the spill at a property on Meadows Road in Washdyke shortly before 1pm.
The building where the spill was located has been evacuated.
A Fire Service spokesperson said firefighters were wearing hazmat (hazardous material) suits.
It was not known what the chemical was.