Military analysts say it will take China longer than a decade to mass produce the J-20, but it still signals a major step forward for the Chinese air force, which is gradually shaking off its dependency on obsolete Russian and Israeli designs.

Andrei Chang, editor-in-chief of the Canadian-based Kanwa Asian Defence Monthly, said the J-20 would have a test flight at Factory 132 in Chengdu in the next few days if the weather was good. 'The testing aircraft will be equipped with a modified WS10 engine that is made in China,' Chang said.

The new stealth fighter was not yet up to the standards of the Russian T-50 and the US F-22, which it aims to emulate, but it showed plenty of potential, he said. It fell short of its US and Russian rivals in terms of stealth technology and cruising speed.

The J-20 is capable of long-range missions with mid-air refuelling, can launch long-range cruise missiles and carry heavy weapon loads. It is also larger than most observers expected.

'This is a very mature and creative design; Chengdu 132 is a successful plant with a real strength,' Chang said, adding that the emergence of the fifth-generation fighter marked the end of the era of imitation for China's military aircraft industry.

Photographs posted on the internet by mainland military enthusiasts show the J-20 has a canard delta layout similar to its sister fighter, the J-10, but with moving vertical stabilisers like Russia's new fifth-generation T-50 fighter. With smaller, canted ventral fins, its stealth body shaping is similar to the American F-22.

Antony Wong Dong, president of the International Military Association in Macau, said the new generation stealth fighter was a key military project in the 10th Five-Year Plan and was driven by two crises in 1999.

'The bombing of China's embassy in Yugoslavia by the US Air Force, and Taiwan's then president Lee Teng-hui's pro-independence 'two-state theory' really got the project going,' he said.

Professor Cheung Tai-ming, a PLA expert at the University of California San Diego's School of International Relations and Pacific Studies, said the J-20 could not form a near-term threat to US air power because the US Air Force would be churning out a large number of fifth-generation F-35 stealth aircraft.

'The big issue is whether other regional countries would see this as a major concern and push for their own acquisition of stealth aircraft,' he said. 'The Japanese are already looking at purchasing the F-35, and the pressure will be on the Taiwanese and South Koreans. Russia and India have also recently signed a major agreement to push ahead with their joint next-generation fighter programme.'

Shanghai-based military expert Ni Lexiong said the internet release of photographs of the J-20 taxiing test might be part of a plan by Beijing to deter its neighbours from involvement in any US-led scheme to contain China. 'The taxi tests were done at the countryside airfield of Chengdu's Aircraft Design Institute at Huangtian Dam, where many military enthusiasts gather regularly to wait for something to happen.

'Whether or not it was a deliberate arrangement, I believe Beijing was skilfully warning its Asian neighbours that besides economic development, China will stick with its principle of building a powerful military.'