May 20 (Bloomberg) -- Tokyo's Haneda airport, Japan's busiest, will offer twice as many slots for international flights as previously planned after a fourth runway opens in 2010, allowing flights to Europe.

The government will allow late-night and early-morning takeoffs and landings, enabling the airport to handle 60,000 overseas flights a year, up from an original plan for about 30,000, according to a document from the Japanese transportation ministry.

Japan is increasing overseas flights at Haneda and Narita International Airport, its busiest overseas gateway, to make Tokyo more attractive as a financial center. A high-speed rail link between Tokyo and Narita is scheduled to open in 2010, cutting the journey time to the airport from Nippori station in Tokyo to 36 minutes from 51 minutes.

Haneda will add 30,000 international slots during the day, serving Asian cities such as Seoul, Shanghai, Beijing and Hong Kong. It will also allow 30,000 slots from 11 p.m. to 6 a.m., primarily to European and other worldwide destinations, as it becomes a 24-hour airport, according to the government.

Japan will also add 20,000 international slots annually at Narita as the airport extends one of its two runways in 2010.

To contact the reporter on this story: Chris Cooper in Tokyo at ccooper1@bloomberg.net

Last Updated: May 20, 2008 06:54 EDT