China will begin construction of a permanent manned space station in 2019 after carrying out a successful in-orbit refuelling from its Tianzhou-1 cargo spacecraft, officials leading the project said on Friday.

The Tianzhou-1, China's first cargo spacecraft, launched on April 20 and completed the first of three planned docking attempts with the orbiting Tiangong-2 spacelab two days later, state media reported.

The successful five-day refuelling, directed from technicians on Earth and completed on Thursday, is a key milestone towards China's plans to begin sending crews to a permanent space station by 2022.

"This again announces the ambition and aspiration of the great rejuvenation of the Chinese people, and our resolute confidence in becoming a major space power," the space station project's supervisor Wang Zhaoyao told a news briefing in Beijing.

"After completing experimental stage spaceflight missions, we will enter the development and construction phase. According to our plans we will carry out the assembly and construction of China's manned space station between 2019 and 2022."

President Xi Jinping has prioritised advancing China's space programme to strengthen national security. The Central Military Commission, chaired by Xi, sent a letter congratulating staff of the Tianzhou-1 mission for "realising our unremitting space dream", according to the official Xinhua news agency.

The US Defense Department has highlighted China's increasing space capabilities, saying it was pursuing activities aimed at preventing other nations from using space-based assets in a crisis.

China insists it has only peaceful ambitions in space, but has tested anti-satellite missiles.