SINGAPORE — Singapore's Changi airport opened a third terminal, allowing it to handle 50 percent more passengers as the city-state fends off competition from newer airports to be the region's travel hub.

The $1.2 billion Terminal 3 will enable Singapore to tap the "robust" growth in air travel in the Asia Pacific region, Transport Minister Raymond Lim said today. The arrival of a Singapore Airlines Ltd. Boeing Co. 747 at around noon marked the opening of the terminal.

Singapore, facing competition from newer and bigger airports in Kuala Lumpur, Malaysia, and Dubai in the United Arab Emirates, has already added a terminal for low-cost airlines and Asia's first stand-alone luxury terminal. The aviation industry accounts for about 8 percent of the city's economy and 7 percent of total employment.

"Singapore faces rising competition in the north with Hong Kong, and to the west with Dubai," said Derek Sadubin, chief operating officer of the Sydney, Australia-based Centre for Asia-Pacific Aviation, an industry consultant. "Kuala Lumpur is also ... becoming a low-cost hub for the region."

Governments are building new terminals and upgrading existing facilities as rising incomes and the entry of at least 18 low-cost carriers in the region since 2001, including Singapore-based Tiger Airways Pte and Malaysia's AirAsia Bhd., spur demand for air travel.

Airports of Thailand Pcl, the operator of the country's main airfields, said in September it may expand Bangkok's new international airport, increasing capacity by 22 percent to 55 million passengers a year. Bangkok opened a new $4.7 billion airport in 2006.

The sheikdom of Dubai, in the United Arab Emirates, is building a new airfield that will be 10 times the size of the existing international airport.

Beijing Capital International Airport Co., the operator of Asia's second-busiest airfield that is building a third runway and a new terminal, expects to handle more than 60 million passengers in 2008. Malaysia Airports Holdings Bhd., which runs 39 airfields in the country, expects to handle as much as 5 percent more passengers at its international airport this year from the 26 million visitors in 2007.

Passenger air traffic worldwide is forecast to jump 29 percent to 2.75 billion passengers by 2011, from 2.13 billion in 2006, threatening to overwhelm airports, according to International Air Transport Association, or IATA, which represents about 240 airlines globally.

"We expect international air passenger traffic in Asia to grow 5.9 percent between 2007 and 2011 and that means over 300 million additional passengers compared to today," said Albert Tjoeng, a spokesman at IATA. "So, airports in Asia need to continue planning and investing in additional capacity in order to keep pace with expected traffic growth."

The new facility will boost capacity to 66 million passengers a year, from 44 million. It is equipped with 28 aerobridge gates, eight of which are capable of handling the Airbus SAS A380, the world's largest commercial aircraft. Singapore Air, the first to fly the A380, started services last year.

China Eastern Airlines Corp., Qatar Airways, India's Jet Airways and United Airlines will also operate from the new terminal from March, the Civil Aviation Authority of Singapore said in a statement today.

Terminal 3, with more than 100 retail shops and 40 restaurants and cafes, will also add to earnings. The Civil Aviation Authority, which runs the city's main passenger terminals, had net income of $286 million for the year ended March, compared with $309 million the year before, according to its annual report.

Singapore, aiming to triple tourism revenue to $21 billion by 2015, is preparing to host more visitors as governments work to free air links in the region. The 10-member Association of Southeast Asian Nations is working to fully liberalize aviation services by 2015.

To stay ahead, Singapore also spent $166 million to refurbish the 17-year-old Terminal 2, which has annual handling capacity of 23 million passengers.

Changi airport, Asia's fifth-busiest, started operations in 1981 with one passenger terminal building, costing $403 million, with a handling capacity of 21 million passengers a year. The second terminal cost $578 million to build and opened in 1990. The airport now serves 83 airlines connecting more than 180 cities through a record 4,300 weekly flights.