Boeing faces a fresh delay in the resumption of deliveries of 737 MAX jets to China after the mid-air blowout of a panel on an Alaska Airlines MAX 9 this month, the Wall Street Journal reported on Sunday.

China Southern Airlines had been readying to receive MAX planes in January, but it plans to conduct additional safety inspections on the aircraft, the report said, citing people familiar with the matter.

China's aviation regulator also instructed the country's airlines to conduct precautionary safety inspections on their Boeing 737 MAX jets, the report added.

Chinese airlines do not have the MAX 9 model in their fleet. The MAX 8 jets they operate lack the panel involved in the Alaska Airlines incident.

Beijing is holding off from making further substantive moves as it waits for more clarity from U.S. investigations into the accident, the WSJ reported, citing a person familiar with the matter.

Boeing declined to comment. China Southern Airlines and China's aviation regulator did not immediately respond to Reuters' requests for comment.

China suspended most orders and deliveries of Boeing planes in 2019 after 737 MAX was grounded worldwide following two fatal crashes in Indonesia and Ethiopia.

A restart of MAX deliveries would be a major breakthrough for Boeing's relationship with China, which has been impacted by the MAX crisis and U.S.-China political tensions.

It would also be a financial win for Boeing, allowing it to collect payment for dozens of Chinese MAX planes in its inventory.

The company last month made its first direct delivery of a 787 Dreamliner to China since 2019, a step seen as a possible prelude to the end of Beijing's freeze on MAX deliveries. Through November, it also handed over eight 777 freighters to Chinese customers, according to Boeing data.

Boeing has been virtually frozen out of new orders from China since 2017 amid Sino-U.S. trade tensions. (Reporting by Gokul Pisharody in Bengaluru and Sophie Yu in Beijing; Editing by Christian Schmollinger and Jamie Freed)