Chinese leaders have given final approval for a long-awaited new international airport in Beijing, costing $11.2 billion, to ease crushing congestion at the existing facility, state-run media said Monday.

The huge new airport south of the capital will have six runways for civilian aircraft and a seventh for military use, the China Daily said, citing CAAC News, a paper linked to the country's civil aviation administration.

Approval of the airport comes despite China's Communist leaders saying they want to retool the economy away from such big ticket infrastructure projects, which have been a key driver of economic growth in recent decades.

Beijing Capital International Airport, north of the city, has been ranked as the world's second busiest airport for three years, handling 81.8 million passenger movements in 2012, the China Daily noted.

"The plan for a new airport has been approved by the State Council (China's cabinet)," it quoted a Beijing aviation spokesman as saying.

Official confirmation was not immediately available.

Reports said the new airport was scheduled to open by the end of 2018 and have a capacity of 70 million passengers a year by 2025.

It will cost at least 70 billion yuan ($11.2 billion), CAAC News reported, adding that the proposal was made as long ago as 2008 but not approved by the Central Military Commission until the end of last year.

The military enjoys priority over China's airspace, which has worsened congestion for civilian flights forced to ply narrow air corridors.

"The current law on civil aviation was made in 1995, and it should be revised after 18 years of tremendous changes in society and rapid economic development," the China Daily quoted Liu Weimin, professor at the Civil Aviation Management Institute of China, as saying.

Beijing Capital -- the world's second busiest airport after Hartsfield-Jackson in Atlanta -- saw a major expansion in the run-up to the 2008 Olympics, reflecting China's relentless economic rise, but passengers have long complained of delays.

A new airport would put Beijing alongside the likes of New York, London, Paris and Tokyo as cities with more than one major facility.