The Shenzhou-19 crew have been working on Beijing's Tiangong space station since October and were scheduled to descend to Earth on Tuesday afternoon.

"Because the recent meteorological conditions at the Dongfeng landing site do not meet the mission requirements... (the mission) will be postponed and implemented at an appropriate time in the near future," Xinhua news agency said.

The delay would "ensure the lives, health and safety of the astronauts and the successful completion of the mission", it added, citing the China Manned Space Program (CMS).

The trio -- Cai Xuzhe, Song Lingdong and Wang Haoze -- have carried out experiments during their six-month stay on Tiangong and set a new record for the longest ever spacewalk.

Wang, 35, was China's only woman spaceflight engineer at the time of the launch, according to the CMS.

Commander Cai, a 48-year-old former air force pilot, previously served aboard Tiangong as part of the Shenzhou-14 mission in 2022.

Song, a 34-year-old one-time air force pilot, completes the group of spacefarers popularly dubbed "taikonauts" in China.

Their three replacements arrived on the space station last week after blasting off from a remote desert base in the country's northwest.

Beijing has ploughed billions of dollars into its space programme in recent years in an effort to achieve what President Xi Jinping describes as the Chinese people's "space dream".

The world's second-largest economy has bold plans to send a crewed mission to the Moon by the end of the decade and eventually build a base on the lunar surface.

China's space programme is the third to put humans in orbit and has also landed robotic rovers on Mars and the Moon as it catches up with the two most established cosmic powers, the United States and Russia.

Crewed by rotating teams of three astronauts every six months, Tiangong -- whose name means "celestial palace" in Chinese -- is its tour de force.