China's leader-in-waiting Xi Jinping has travelled extensively in the last two years as vice-president, but next week's US visit will provide the greatest test he has yet faced abroad.

Analysts said Xi's every move would be closely scrutinised during the trip, which will include talks with US President Barack Obama and a speech in Washington before he heads on to Iowa and Los Angeles.

The visit "must place Xi Jinping in the position of statesman and confirm his ability to express himself on international affairs," said Francois Godement, head of strategy for the Asia Centre in Paris.

"But it is also a test... his views are not very well known," he said of the often impassive 58-year-old. "He will be judged on his communication skills, and his ability to reveal some of his character."

Observers will be watching to see whether Xi follows the lead of Hu, who remains as enigmatic now as he was when he took on the role a decade ago, said Godement.

Barring a last-minute coup-de-theatre, Xi will take over from President Hu Jintao as leader of China's ruling Communist party at the 18th congress to be held in October, and as head of state in March 2013.

Michel Bonnin, head of the Franco-Chinese department of the Tsinghua University in Beijing, said the US visit was "part of the preparations for handing over the baton."

"It's one of the final stages," said Bonnin, an expert on China's Communist party. "He must not make any 11th-hour mistakes."

But Bonnin stressed that Xi's background meant he was much more at ease outside China than Hu. "Hu was a product of the (Communist youth) league, while Xi is a princeling," he said.

China's princelings are those leaders whose family lineage has played a part in their success -- Xi's father was Xi Zhongxun, a communist hero who fought alongside Mao Zedong.

Bonnin said Xi belonged to a generation of Communist leaders groomed for power since the 1980s who had "knowledge of and links to the outside world", and that the vice-president would be comfortable speaking English.

Xi already has links with the United States, where his daughter is studying at Harvard University under an assumed name to protect her anonymity.

He made friends in Iowa when he travelled there in 1985 as a low-ranking official, and he will return to the state after holding talks in Washington.

Xi's main mentor was not Hu Jintao, but China's former president Jiang Zemin, who Godement said was "indisputably the Chinese leader who did the most for Sino-US relations."

Nonetheless, China's likely next president will face several potential pitfalls during his US trip.

Among them are Beijing's decision -- sharply condemned by Washington -- to veto a UN resolution criticising Syria for its bloody crackdown on protests, and a spate of self-immolations in China's Tibetan areas.

Trade tensions between the two countries have increased in recent months, while anti-China sentiment has risen, fuelled by negative campaigning in the run-up to US elections.

China's Vice Foreign Minister Cui Tiankai this week warned of a "trust deficit" between Beijing and Washington and expressed hopes Xi's visit would strengthen ties.

Peking University's Wang Dong said the visit had a dual message -- to signal to the United States that Xi would soon be in charge and to "enhance mutual trust" at a time when relations between the two powers were "at a critical crossroad".

But Bonnin said Xi's "skillful and cautious" approach would go a long way to helping the trip pass off smoothly.

Xi would not go out of his way to "clearly differentiate himself from Hu Jintao" -- at least not until he is in power -- Bonnin added.

"He will aim for a cautious approach, he could still incur losses," said one Western diplomat who asked not to be named, referring to the current fight for places in the Politburo, the heart of power in Beijing.

In recent years, Xi's travels have taken in Australia, Chile, Italy, Russia, Angola, South Africa, Singapore and Thailand among others.

His trips have been largely free of incident -- with one notable exception in Mexico in 2009, when he delivered a surprise diatribe against foreigners "with full bellies" who "have nothing better to do than to point fingers" at China.