The fire at the Dongwha Pattina plant has been extinguished.
Mataura fire chief Neil Rogen said the small blaze started in the Vitec building on the Dongwha factory site.
The building is used by a seperate business to the main Dongwha fibreboard factory.
''Some board went on fire on their assembly line,'' Rogen said. ''Pretty much by the time the brigade got there the workers had dealt with it.''