The cause of a fire which razed a Greerton building is under investigation.

Flames and smoke were seen billowing from the building on Cameron Road this morning.

When firefighters were called to the blaze at 4.25am, the 10mx10m automotive building was 'well involved”.

Fire and Emergency New Zealand northern communications shift manager Daniel Nicholson says they received multiple calls from people who had seen the fire.

'We have two trucks still at the scene dampening down hot spots.

'A fire safety investigator has been called to the scene and it's still too early to say what caused the fire.”

Around 20-25 firefighters from Greerton, Tauranga and Mount Maunganui attended the fire.

Cameron Road is reported to be open now.