Chinese web users slammed billionaire Elon Musk on Tuesday after Beijing said its space station took evasive action to avoid hitting two of his SpaceX satellites, dealing a blow to the tycoon's reputation in a country that has embraced his Tesla electric cars.

China's Tiangong space station was forced to take "preventive collision avoidance control" during two "close encounters" with SpaceX's Starlink satellites in July and October, according to a document submitted to the UN's space agency by Beijing this month.

On both occasions, the satellites moved into orbits that prompted space station operators to change course, the document said.

"The manoeuvre strategy was unknown and orbital errors were hard to be assessed", Beijing said of the satellite involved in the October incident, adding that it took action to "ensure the safety and lives of in-orbit astronauts".

Tiangong -- meaning "heavenly palace" -- is the latest achievement in China's drive to become a major space power, after landing a rover on Mars and sending probes to the Moon.

Its core module entered orbit earlier this year, with the station expected to be fully operational by 2022.

Chinese social media users blasted Musk and his companies over the incident, with one hashtag racking up 87 million views Tuesday.

"How ironic that Chinese people buy Tesla, contributing large sums of money so Musk can launch Starlink, and then he [nearly] crashes into China's space station," one user commented.

SpaceX's Starlink is a constellation of more than 1,700 satellites that aims to provide internet access to most of the Earth.

"Prepare to boycott Tesla," said another, echoing a common response in China to foreign brands perceived to be acting contrary to Beijing's national interests.

Some speculated that Washington would have imposed sanctions if the roles were reversed.

"Why don't we just do what they do?" one wrote.

California-based SpaceX has not responded to a request for comment.

Evasive manoeuvres are becoming more frequent as more objects crowd into near-Earth orbit and force course adjustments to reduce the risk of crashes, said Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics.

"We've really noticed the increase in the number of close passes since Starlink started getting deployed," he told AFP, adding that any collision would likely "completely demolish" the space station and kill everyone on board.

Although Musk is widely admired in China, the reputation of Tesla -- which sells tens of thousands of vehicles in the country each month -- has faltered this year following a spate of crashes, scandals and data storage concerns.

But Tesla is still hugely popular, selling around one out of every four of its cars in China, and has built a rare wholly-owned factory in Shanghai.