China has put its name down in a repeat of dominating performance on home ground as the clock ticks down to London Olympic Games.

"It won't be a Beijing do-over for us. We face unprecedented difficulties in catching up with the gold haul of Beijing without home advantage," said Xiao Tian, deputy chef de mission of the Chinese Olympic delegation.

"But I have full confidence in Chinese athletes and believe they will have excellent achievements in London," he said at a press briefing on Wednesday.

Xiao kept a lid on soaring expectations, encouraging new breakthroughs of Chinese athletes without making any bold predictions.

"I hate to predict how many gold medals we are going to claim," said Xiao, laughing a little as he added: "I did it in the past but every time it turned out to be wrong."

"I don't want myself to be labeled as 'crow mouth' just like the famous soccer player Pele," he added.

Xiao hoped Chinese athletes would keep their mood light, train even harder and brace themselves to give a best performance in London.

China fielded a streamlined London team with 396 athletes including 29 gold medallists from the Beijing Games. The players, 171 male and 225 female, are to compete in 212 disciplines of 23 sports expect for football, equestrian and handball.

According to Xiao, the average age of Chinese athletes is 24.6, with swimmer Qiu Yuhan the youngest at 14 and trapshooting player Liu Yingzi eldest at 41.

Most of Chinese athletes had moved in the Olympic village in London with four sports teams still training in the cities nearby.

Four years ago, China topped the medals table with 51 golds at home, when it sent a record-breaking 639 athletes to compete in the Beijing Games. It outshone the United States which finished with 36 golds but edged China in overall medals 110 to 100.

Xiao played down China's chances to hold off the United States for another time, adding the United States is a traditional sports powerhouse which outpaces China in many of the Olympic sports such as team balls events.

Thirty-eight of China's table-topping 51 gold medals in Beijing came in table tennis, badminton, diving, shooting, gymnastics and weightlifting which the country has long dominated in.

But in London, China is looking forward to breakthrough in what are considered more prestigious Olympic sports, including swimming and track and field.

"We do have expectations on breakthroughs in such sports as swimming, fencing, judo and cycling," Xiao said, citing overwhelming Chinese swimmer Sun Yang and 110m hurdler Liu Xiang.

Sun, who smashed Grant Hackett's decade-old 1,500m world record at the Shanghai World Championships last year, is tipped to become China's first Olympic male swimming champion. Currently he ranks world number one in the 400m, 800m and 1,500m freestyle.

Liu, whose back injury forced him out of the London Diamond League final earlier this month, has bounced back in true champion style as he registered a world record-tying time of 12.87 seconds at last year's World Championships.

"What I worry most is the team ball events which we still have a lot to improve in order to be a true sports powerhouse," Xiao said.

The five team ball events China would participate in London are men's and women's basketball, women's hocky, women's water polo and women's volleyball.

Xiao confirmed basketball player Yi Jianlian would carry the flag for China at the Games opening ceremony, adding the NBA player has good sport ethics and well represents the image of China, and most importantly, would have impact on huge Chinese basketball fans.

Yi, 24, started his career as a professional player in south China's Guangdong Province. He joined NBA in 2007 and played for the Washington Wizards before he came back to China amid the NBA lock-out.

What's interesting, the national flag bearers for Chinese delegations since 1984 have been selected from the men's basketball team.

Wang Libin was China's flag bearer in the opening ceremony of 1984 Los Angeles Olympic Games, Song Tao for 1988 Seoul Olympics, Song Ligang for the 1992 Barcelona Games, Liu Yudong for 1996 Atlanta Olympics and 2000 Sydney Olympic Games. Former NBA star Yao Ming was the flag-bear of the Chinese sports delegation at both Beijing 2008 and Athens 2004.

"We will take into consideration to appoint a woman athlete to carry the flag in the future based on her impressive sports record and personal influence," Xiao noted.

He expressed satisfaction over the environment and catering in the Olympic village, adding Chinese athletes would enjoy competing and enhancing exchanges with competitors worldwide during the Games slated from July 27 to August 12.