The hole was found in a pipe linked to the platform's flaring system and resulted in 159 workers being sent to their living quarters.
Statoil spokesman Oerjan Heradstveit told Reuters that the company would repair the hole as soon as possible but that it couldn't say how long it would take.
Gullfaks was once one of the biggest fields in Norway and is one of the most mature projects.
The company maintains the shutdown was taken as a precautionary measure.