China's space program must help protect the country's national security, but the country is dedicated to the peaceful use of space and opposes a space arms race, the Chinese Government says in a newly released policy paper.

President Xi Jinping has called for China to establish itself as a space power, and it has tested anti-satellite missiles, in addition to its civilian aims.

China has repeatedly said its space program is for peaceful purposes, but the US Defence Department has highlighted its increasing capabilities, saying it was pursuing activities aimed to prevent adversaries from using space-based assets in a crisis.

In its policy paper, the Government said the space program was an important part of the China's overall development strategy.

The program must also "meet the demands of economic, scientific and technological development, national security and social progress", the paper said, without elaborating on the security part.

"China always adheres to the principle of the use of outer space for peaceful purposes, and opposes the weaponisation of or an arms race in outer space," it said.

Past weapons tests were included as part of the history of China's space program, which the military has always been deeply involved with.

"Over the past 60 years of remarkable development since its space industry was established in 1956, China has made great achievements in this sphere, including the development of atomic and hydrogen bombs, missiles, man-made satellites, manned spaceflight and lunar probes," it said.

China completed its longest manned space mission to date last month, when two astronauts spent 30 days aboard the Tiangong 2, or Heavenly Palace 2, space laboratory.

China is using the lab to carry out experiments ahead of a longer-range plan to have a permanent manned space station around 2022.

The white paper also repeated a plan to launch its first Mars probe by 2020, and to land the first probe on the dark side of the Moon in 2018, but gave no details about a previously mooted goal of landing a Chinese person on the moon by 2036.

Reuters