Cruise passengers in Southampton were told their holiday was on hold today.
Around 450 people were looking expecting to board the Saga Ruby this afternoon, ready for departure from the docks this evening.
But checks carried out by staff this morning revealed a problem with the ship's crankshaft.
Saga says it could cause a delay of up to two weeks to the 100-night cruise.
Director of communications Paul Green said: “Earlier it was discovered there were mechanical problems with the crankshaft of the ship.
“That's going to need to be properly repaired before the round-the-world cruise can set off. “It's not a simple repair, its going to take a week or so to actually affect the repair.
“Unfortunately we have had to delay the start of the cruise, so clearly that's come as a great disappointment to us and also to the passengers that we have had to contact.
“Given that the issue was only discovered this morning, we don't know precisely how long it will take to obtain the right replacement parts.
“The best estimate is it will take one to two weeks to complete.
“Saga will do the right thing by our customers, and that will involve an element of compensation.
“Our focus is on finding the right parts and finding the right people to effect the repair so we can get this fantastic cruise programme started.”