The Maritime and Coastguard Agency has told us that officials went on board the Discovery at the end of last week as part of a routine inspection, and found a number of issues with 'safety management systems'.
This related to crew familiarisation of the ship and training.
The MCA ordered that the vessel should remain in place until the owners had made a number of improvements.
Seven hundred passengers have been told that their cruise, a two-week trip around Norway, has been suddenly cancelled.
The Discovery was originally scheduled to sail from Avonmouth near Bristol but, due to tidal restrictions, it was re-routed to Portland in Dorset at the end of last week.
24 coaches transferred all passengers to Portland but the Captain then informed everyone on board that the cruise could not go ahead due to 'technical reasons'.
Passengers will all receive a full refund and £250 compensation per person.
The firm says that Discovery should be ready for its next scheduled departure from Avonmouth on March 15th.