Beijing on Monday rejected as an irresponsible smear a warning from the chief of Nasa that China might "take over" the moon as part of a military programme, saying it has always called for the building of a community of nations in outer space.

China has stepped up the pace of its space programme in the past decade, with exploration of the moon a focus. China made its first lunar uncrewed landing in 2013.

Foreign Ministry spokesperson Zhao Lijian told reporters China has always promoted the building of a shared future for humanity in outer space and opposed its weaponisation and any arms race in space.

Zhao was responding to claims by the US space agency chief, who said China's space programme was a military one.

"We must be very concerned that China is landing on the moon and saying: 'It's ours now and you stay out'," Nasa Administrator Bill Nelson told German newspaper Bild in an interview published on Saturday.

At a Monday press conference, Zhao said: "This is not the first time that the head of Nasa has ignored the facts and spoken irresponsibly about China."

"The US side has constantly constructed a smear campaign against China's normal and reasonable outer space endeavours, and China firmly opposes such irresponsible remarks."

Nasa, under its Artemis programme, plans to send a crewed mission to orbit the moon in 2024 and make a crewed landing near the lunar south pole by 2025.

China is planning uncrewed missions to the moon's south pole some time this decade. (Reuters)