SHENZHEN, which has morphed from a low-cost manufacturing center into a booming “Chinese Silicon Valley” technology hub, poses a rising threat to Hong Kong’s regional domination in international air travel.

Shenzhen’s airport has long been a busy domestic hub, with 38 million passengers flying within the Chinese mainland last year, but moved fewer than 3 million on international flights.

Now, operator Shenzhen Airport Co. says it aims to grow international air traffic to 15 million passengers by 2025 — a fifth of its total.

That’s still far below the 82 million passengers that Hong Kong will accommodate by then, according to IATA Consulting projections — around 80 percent of whom will fly to and from destinations outside the mainland, if today’s traffic trends analyzed by air travel data group OAG are maintained.

But mainland airlines’ cheaper labor costs, and better road and rail links mean Shenzhen could wrest some of the growth from Hong Kong in the years ahead.

Guangzhou, the capital of Guangdong Province, which also includes Shenzhen, saw 13.5 million international passengers last year.

Shenzhen’s growth comes after the government upgraded it to an “international aviation hub” under its five-year plan in 2016, matching the status of Beijing, Shanghai and Guangzhou. Nearby Zhuhai and Macao airports were not upgraded.

Some analysts predict Shenzhen’s gross domestic product will overtake Hong Kong’s next year.

The rise of Shenzhen has posed something of a dilemma for Air China Ltd., majority owner of Shenzhen Airlines, which also has a 30 percent stake in Hong Kong’s Cathay Pacific Airways Ltd.

Air China has been wary of adding long-haul flights out of Shenzhen that could challenge Cathay, said three aviation industry sources who declined to be named.

But the airline is concerned that rivals China Southern Airlines Co. and Hainan Airlines Holding Co. are stepping in to add international flights which the local government is encouraging to boost the economy.

China Southern now flies to Sydney, Melbourne and Moscow, while Hainan has added a Brisbane service from Shenzhen, where a new modernist terminal boasts a dome ceiling that floods the building with natural light. (SD-Agencies)