China's green-light is a boost to the planemaker, which has been hit by the fallout from a mid-air blowout of a cabin panel on a 737 MAX 9 jet operated by Alaska Airlines, including the U.S. Federal Aviation Administration barring Boeing from expanding production of its best-selling narrowbody planes.

The emergency resulted in the aviation regulator grounding 171 737 MAX 9 jets and the cancellation of thousands of flights by U.S. carriers.

"What I can tell you here is that on Dec. 8, 2023, the Chinese department in charge completed the design approval of the Boeing 737 MAX 8 in accordance with China's civil aviation regulations, the aircraft is ready for delivery," Chinese Foreign ministry spokesman Wang Wenbin said, when asked about Boeing's delivery of a 737 MAX 8 to China Southern Airlines late on Wednesday.

Boeing did not immediately respond to a request for comment.

China is one of the fastest-growing aerospace markets, which Boeing projects will account for 20% of the world's aircraft demand through 2042.

It was China that first grounded MAX jets after two accidents in 2018 and 2019 that killed nearly 350 people.

While safety bans have been lifted, new deliveries had remained on hold as tensions between Washington and Beijing over issues ranging from technology to national security intensified.

"It is certainly an encouraging sign that this aircraft is headed to China, but it remains to be seen how rapidly Chinese carriers accept 737s," said Greg Waldron, Asia managing editor of industry publication FlightGlobal.

"Beijing's decision calculus for taking Boeing aircraft is opaque. While taking 737s could be seen as an effort to appease Washington DC, it could also be that the airlines have pressed for new aircraft," he added.

The 737 MAX 8 registered to China Southern Airlines left Seattle Boeing field in Washington state at 11:55 a.m. Pacific Time (1955 UTC) on Wednesday and in the first leg across the Pacific landed in Honolulu almost seven hours later, flight data from FlightRadar 24 shows, before resuming its journey.

China Southern and the Civil Aviation Administration of China, did not respond to requests to comment.

(Reporting by Eduardo Baptista and Sophie Yu in Beijing; Lisa Barrington in Seoul and Valerie Insinna in Washington; Writing by Brenda Goh; Editing by Christopher Cushing and Miral Fahmy)

By Eduardo Baptista and Sophie Yu