Large explosion at factory near Taupo

Fire fighters attending a blaze north of Taupo tonight were greeted with a large explosion from inside a burning factory.

Alarms alerted emergency services to smoke at Nature's Flame pellet factory in Rotokawa, 11km northeast of Taupo, about 8.50pm, said Fire Service spokesman Jaron Phillips.

"The first crews that arrived reported a dust explosion inside the building as they arrived," he said.

Two sawdust hoppers had caught alight, and 11 fire appliances from as far away as Rotorua and Tokoroa were assisting with the effort.

Mr Phillips said between 40 and 50 fire fighters attended the blaze and there were no reports of injuries.

The three storeyed factory measured 50m by 80m, said Mr Phillips.

Crews had the blaze under control quickly and left the site by 11pm.