Emergency services were called to the Fonterra factory in Edendale after a chemical spill on Tuesday morning.

Firefighters are cleaning up a chemical spill at a Fonterra factory near Invercargill.

Invercargill fire service assistant area commander Deane Chalmers said there was a chemical spill of two substances at the plant about 2am on Tuesday.

About 5000 litres each of nitric acid and caustic alkali had leaked, however the chemicals had been caught by their respective safety catchment areas.

The spill was "significant" but the chemicals did not mix, Chalmers said.

There were no injuries caused by the chemical spill.

The fire service was in the process of securing the scene and had been worried about the two chemical mixing, because the reaction would have produced a toxic, corrosive gas, Chalmers said.

Fire crews from Edendale, Wyndham, Invercargill and volunteers from Mataura attended the scene.

External cleaning company Cleanways was on site to help clean up.

Nitric acid and caustic alkali are used in the plant's cleaning processes, Chalmers said.

Staff were evacuated from the plant, but would be able to return to work when the scene was secured and clean.

Some areas of the plant had re-opened, however Chalmers expected fire crews to be on site for the next hour.

While securing the scene and during the clean up, fire crews used breathing apparatus and level three chemical suits to protect themselves, Chalmers said.