On August 2, Kansai International Airport near Osaka opened its second runway, which will allow it to become Japan's first 24-hour aviation hub.

The expansion comes as Japan tries to increase the number of international flights amid growing competition from other Asian airports, most of which are open around the clock.

The second runway, with a length of 4000 metres, will give Kansai airport the capacity to handle more flights and ease congestion at peak hours.

The airport, built on an artificial island in Osaka Bay, will begin operating 24 hours a day in October, when a new air traffic control system will be ready. The second runway opened weeks before Osaka hosts the World Athletics Championships.

In an opening ceremony, about 400 airport officials stood along the new runway waving their hands as the first flight landed on the new runway, after a journey from Bangkok.

But the runway has also faced accusations of being a pork-barrel project as the airport has struggled to break even since opening in 1994. The airport has interest-bearing debts of 1.18 trillion yen (US$11.5 billion).

Airport authorities argue the 24-hour operation will allow more cargo flights and passenger jets from Asia.

"We are especially looking at surging demand from China," spokeswoman Junko Masutani said.

Narita International Airport near Tokyo, Japan's biggest gateway for foreign travel, is also extending a runway. But Narita is unlikely ever to have 24-hour operations due to longstanding friction with local residents upset by noise.

Japan has built new airports in recent years in the central city of Nagoya, the southern city of Fukuoka and also in Kobe, which is only a short distance from Osaka.

In May, a government panel urged Tokyo Haneda -- a domestic hub that is Asia's busiest airport -- to accommodate more international flights.