Chinese astronauts will give a Chinese-made spacesuit its first real test when they attempt the country's first-ever spacewalk during the Shenzhou VII mission set to blast off late Thursday.

Mastering spacewalk technology is crucial for China's eventual plans to develop a space station as astronauts will need to be able to work outside their spacecraft to make repairs or carry out inspections, experts said.

Government websites have said 42-year-old air force pilot Zhai Zhigang will test the new "Feitian" spacesuit, named for a flying Buddhist goddess.

Another member of the three-man flight crew will join Zhai in a decompressurised orbital module during the manoeuvre, expected Friday or Saturday.

"The spacesuit Zhai will wear is a Chinese design, while that worn by his back-up is Russian," said Joan Johnson-Freese, a specialist on China's space programme at the US Naval War College.

"The Chinese suit has been tested in vacuum chambers, but I think having a back-up in a proven (Russian) suit made out of proven material is prudent, in case of emergency."

The suit is being touted by China as a major breakthrough for the country and its ambitious space-exploration plans

The suit, weighing 120 kilograms (264 pounds), is made of "advanced synthetic fibres" and is so supple that an astronaut could bend over and pick up a coin while wearing it, Chinese state-run media reports have said.

However, it is said to still offer adequate protection from the harsh cold of space and the sun's intense ultraviolet radiation.

Officials have been quoted saying the suit can provide nourishment, water and oxygen for up to seven hours and that drainage systems allow the discharge of carbon dioxide and human waste.

Zhai's backup is not slated to leave the orbital module but will do so in case of any emergency arising from a possible malfunction of the Chinese spacesuit, which reportedly cost up to 160 million yuan (23 million dollars).

According to Morris Jones, an Australian space analyst who writes about China's programme, Zhai will remained tethered to the main spacecraft during the walk via the lifelines providing oxygen and communications.

"They are mainly interested in perfecting the spacesuit and the ability to work in space," Jones told AFP.

According to Chinese press reports, more than 30 technologies will be tested during the mission, including a Chinese made airlock which will depressurise an orbital module ahead of the walk and repressurise it after it is over.

"The orbital module of the spacecraft is like a second crew cabin that doubles as an airlock," Jones said.

"Without an airlock, the entire spacecraft would be exposed to a vacuum during the spacewalk."

China has also installed new technology on its rocket engine to reduce vibrations during the lift off, he added.