There's been a fire at the Heinz Wattie's plant in Hastings.

It broke out at about 2am in an outdoor covered area at the production facility in King Street North, in the centre of town.

Five fire trucks from Napier and Hastings were sent, and three were still present at 5am.

Fire Service spokesman David Meikle said the cause is not yet clear but an investigator is on the way.

He's not sure of the extent of the damage, but says no one was injured.