As naval warfare around the contested Falkland Islands heated up, the British government today threw into havoc the vacation plans of thousands of tourists by announcing the requisitioning of the luxury liner Queen Elizabeth 2 to carry an infantry brigade of about 3,000 troops to the South Atlantic.

The announcement brought back memories of World War II, when the vessel's regal predecessors, the Queen Elizabeth and the Queen Mary, transported tens of thousands of GIs to Britain. The new brigade is made up of two battalions of Welsh and Scots guards, who will forgo their traditional place in the Trooping the Color ceremony for the queen's birthday celebration in June, and a battalion of Gurkha rifles, of Nepalese descent.

Defense Ministry spokesman Ian MacDonald said the ministry "greatly regrets the inconvenience to intending passengers, but the QE's speed, size and facilities make her uniquely suited to carry substantial numbers of troops who must be kept fit and ready for operations, should they be required."

At its top speed of 28 knots, it is estimated that the Queen Elizabeth 2 could reach the Falklands in 10 days.

In addition, two ferries and a container ship are being requisitioned to transport helicopters needed for air support for the brigade. That brings to more than 70 the number of ships, both military and civilian, known to be in the task force strung out over 8,000 miles of the Atlantic Ocean.

The Queen Elizabeth 2 was returning to its home port of Southampton tonight after a crossing from New York. It had been scheduled to take about 1,700 passengers on a 13-day Mediterranean cruise Tuesday.

The $75 million liner, which carries a crew of 1,000, first went into operation in 1969, when several luxury ships were still crossing the Atlantic, including the France and the United States, now long since retired from the transatlantic business. It has four swimming pools, four restaurants, two nightclubs, seven bars, a casino, a theater and numerous other facilities.

The liner's sailing date for the South Atlantic has been set yet because it must be fitted with a helicopter pad. It is expected that the troops will carry out training maneuvers while en route, including firing weapons from the deck.

Personnel from Cunard, the ship's owners, spent the day trying to make alternate arrangements for passengers. Some prospective passengers were going through the experience for the second time in a month, since they had been reassigned to the QE2 after the cruise ship Canberra was requisitioned earlier.