There is a big shout for firefighters in Greymouth, where a commercial building in Tainui Street is well alight.

Seven fire trucks and 50 firefighters are dealing with the blaze.

Fire and Emergency shift manager Andrew Norris says the fire was first noticed just after four o'clock this morning.

He says smoke was initially seen coming from a restaurant, and the fire has since spread to an electrical wholesale business.

Part of Tainui Street is currently closed.