Fire crews have been at the scene in Peterhead since around 3pm, battling the blaze – which started in the factory’s packaging room – at North Bay Pelagic on Kirk Square.
Witnesses have reported loud bangs as the building’s glass windows have smashed due to the intense heat.
The fire has also now spread to an adjacent office building.
Members of the public have been urged to stay away from the scene
Hundreds of onlookers have been at the scene watching as firefighters battle the blaze, however, emergency services are pleading with the public to stay away as they could hinder the work of emergency services.