A Celebrity Cruises vessel crashed into another cruiseship after it broke its moorings in stormy weather in Italy.

Video footage showed the 91,000-gt Celebrity Constellation (built 2002) drifting backwards into the bow of another vessel, named as Costa Cruises' 103,000-gt Costa Magic (built 2004), in La Spezia on Tuesday.

Three tugboats attended the vessels. Both ships have continued on their itineraries.

Celebrity Cruises told Cruise Hive that a squall had made its way across La Spezia.

"The strong winds caused our mooring lines to break from the pier," it added.

"We quickly implemented our safety protocols and manoeuvered within the harbour basin and dropped anchor until the inclement weather passed. There were no injuries and all of our guests are back on board."