Beijing’s new huge multi-billion dollar airport is set to be inaugurated as China celebrates its 70th birthday.

Work was officially completed at the weekend, and is ready for a September 30 opening ahead of the anniversary of the foundation of the People’s Republic on October 1.

Beijing Daxing International Airport will be operating at full capacity of 72 million passengers by 2025, with four runways.

That will be expanded to seven commercial runways and capacity of 100 million by 2040.

That will make it the world’s largest single terminal, the designers say.

It is about 40km from downtown Beijing and will be linked to the city by a new subway line, which is due to undergo a test run in September.

Measuring 700,000 square metres, it is equivalent to the size of a hundred football pitches.

Between Daxing and the existing Beijing Capital Airport, authorities expect air traffic to reach about 170 million by 2025.

China Eastern Airlines and China Southern Airlines will relocate to the new airport along with alliance partners KLM and Delta Air Lines.