The new generation of combat aircraft China proudly showed off at the Zhuhai Air Show in the country's south this week could soon be taking off from a prestigious runway: an aircraft carrier.

Beijing has become increasingly assertive in its ambitions on the high seas -- as demonstrated by recent tensions with old rival Japan -- but still lacks this naval centrepiece.

This looks set to change.

Although it has not officially announced as much, China is working on a carrier and Western experts believe it could be launched as early as next year, though not in a fully operational state.

It is a former Soviet aircraft carrier called the Varyag, currently being refurbished in the port city of Dalian in northeast China.

Rick Fisher, a Chinese military expert at the International Assessment and Strategy Centre in the United States, told AFP the Pentagon estimates China's carrier will start operations by 2015.

"This is a reasonable projection. China could have enough of the carrier air wing flying by that time to start developing carrier operating procedures and fighting tactics," he said.

Fisher said that Chinese leaks to media in Hong Kong and Japan last year indicated that Beijing plans a five-strong carrier fleet, including two nuclear-powered vessels.

Arthur Ding, an expert on the People's Liberation Army, which operates the country's navy, said owning an aircraft carrier is a prestige issue for China, whose 2.3-million-strong military is already the world's largest.

This is particularly so when neighbours -- and rivals -- including Japan and India are already equipped with them, said Ding, of National Chengchi University in Taiwan.

But there is a second, practical reason, he added.

"As China's interests expand globally, the Chinese navy needs to go further outbound, and an aircraft carrier is needed," he said.

China has a nuclear arsenal and the world's second-largest defence budget after the United States -- although experts believe China spends more than it reveals -- but its military capabilities beyond its borders are limited.

As a tool for projecting power, the aircraft carrier is unsurpassed.

"When word of crisis breaks out in Washington, it's no accident the first question that comes to everyone's lips is: where is the nearest carrier?" former US president Bill Clinton once said.

Some Western experts believe the Varyag could be more useful to the Chinese as a means of learning carrier technology than as a naval tool in its own right.

China's defence ministry declined comment on the warship's future role when questioned by AFP.

China has a problem accessing the Pacific Ocean, as it lies beyond an arc of rival powers: South Korea, Japan and Taiwan, as well as US bases.

Beijing, envious of Washington's naval dominance, has reacted with resentment to recent US manoeuvres in the China Sea and Yellow Sea, which it considers its backyard. The presence of US carriers compounded the insult.

Fisher said that while China seeks to "cover its growing iron fist in the velvet glove of 'soft power'," acquiring carriers is vital for China's strategic vision.

"China seeks to become a global superpower capable of defending its increasingly international political-economic interests with greater levels of military might," he said.

"Building a fleet of aircraft carriers will be essential to this goal."

China cultivates the image of a country that arms itself solely for self-defence and has no interest in becoming a dominant power.

Developing aircraft carriers could tarnish that image.

Ding said that is why Beijing has been coy about its plans -- it worries the carrier will feed fears about China's rise.

But Chinese enthusiasm for carriers is not confined to the military headquarters. The population seems to be strongly behind building them as standard-bearers for national pride.

A poll by China's state media found 98 percent of people think it is time the nation had an aircraft carrier, and 71 percent think at least four are needed.

The fortnightly Chinese magazine "Modern Ships" launched a design competition for carriers in 2007 and still receives impassioned contributions, according to deputy editor Cui Yiliang.

"Most Chinese people think the navy's abilities do not match the country's needs," he said.