Crews were dispatched from Edendale, Wyndham, Mataura and Invercargill at 7.46am and 8.26am after alarms went off at two different locations at the site, a Fire and Emergency New Zealand spokesperson said.
The teams, with breathing apparatus, were investigating why the alarms had gone off at opposite ends of the plant.
There was no sign of fire and no reports of injuries.
An alarm technician had been called.