Heavy machinery, petrol and agriculture sprays may be inside a farm shed which is on fire on Wairoa Road, just outside Tauranga.

Northern Fire Communications shift manager Daniel Nicholson says crews from Tauranga and Greerton are now at the scene working to extinguish the shed fire, which measures 10m by 12m.

'The caller who alerted us to the fire told us there was machinery kept in the shed as well as petrol and sprays, but that hasn't been confirmed by crews yet.

'When crews arrived they found the farm shed fully involved in a fire measuring 10m by 12m. Crews are currently working to extinguish the fire and protect exposures.”

Three crews in total, two from Tauranga and one from Greerton, are currently at the scene. A fourth, Greerton's water tanker, has also been dispatched and is currently on route to the fire.