Meyer Werft firefighters extinguished the blaze, which occurred on Wednesday. Employees had to leave the affected areas, and work resumed after a temporary suspension.
Information about the cause of the fire and the extent of damage were not immediately available. Unconfirmed news reports estimated the damage at about €50,000.
Extensive security and alarm systems are installed during construction so the yard could respond very quickly, Meyer security manager Martin Eggengoor said.
Norwegian Cruise Line is building Norwegian Joy for the China market. Delivery is scheduled for the spring.