The QE2 was being guarded by police today after docking at Alexandria in Egypt following a security threat against the Southampton-based liner.
Carol Marlow, president of the QE2's owners Cunard, said that the company had received "certain information" and had acted upon it by increasing security surrounding the 67,000-tonne vessel.
She added: "We take these sort of things very seriously and, while we do not actually believe there is any cause for alarm, we have put the ship on a higher level of security.
"We are working with the Egyptian authorities and shore security has been increased. All our excursions from the QE2 are going ahead as planned."
A spokesman for the UK Department for Transport said today: "We are aware of some information concerning the security of the QE2. We treat all such information very seriously and we have acted upon it.
"We are in contact with the operator of the ship and are continuing to monitor the situation carefully."
The QE2 is a 109-day world cruise which started from Southampton on January 3rd and will end at the Hampshire port on April 23rd.
The liner has around 1,700 passengers on board and her next port of call is Kusadasi in Turkey.
Agencies