China said Thursday cleaner fuel will power its next-generation rockets, which will launch heavy cargoes into space, bringing nearer plans to build a space station and put a man on the moon.

In a white paper outlining its ambitious space programme's five-year plan, the China National Space Administration (CNSA) said the Long March-5 rockets "will use non-toxic and pollution-free propellant".

Speaking at press briefing outlining the paper, CNSA spokesman Zhang Wei said the rockets would be capable of placing 25-tonne payloads into near-Earth orbit.

China holds up its space programme as a symbol of the nation's growing global stature and technical expertise, and of the ruling Communist Party's success in turning around the fortunes of the once poverty-stricken nation.

Morris Jones, an independent space expert based in Sydney, told AFP the announcement was significant.

"It's impressive that China's reached that stage with this next round of heavy-lift vehicles, so crucial to reaching their goal of building a space station by 2020," he said.

China's space agency said previously announced plans would go ahead over the next five years, among them establishing a launch pad on the southern island of Hainan, launching lunar orbiters and probes and researching a manned moon landing.

The white paper offered no timetable for plans to launch and dock the Shenzhou IX and X rockets onto China's Tiangong-1 experimental space module in 2012. At least one of these rockets is expected to be manned.

In November, the unmanned Shenzhou VIII spacecraft returned to Earth after completing two space dockings with Tiangong-1 in the nation's first ever hard-to-master "space kiss", bringing together two vessels in high speed orbit.

Appearing to try to allay international concerns about China's potential militarisation of space, the agency said China wanted to "utilise outer space for peaceful purposes" -- a claim Morris disputed.

"No nation that has a respectable major space programme has an entirely peaceful programme," he said, noting China had tested anti-satellite weapons by blowing up one of its own in 2007.

"The world over, space technologies are used for military communications and to deploy spy satellites. China's no different," Jones said.