China's first male world champion swimmer, Zhang Lin, will not compete in the 800m freestyle at July's Shanghai World Championships, abandoning his chance to defend the title he claimed two years ago in Rome.

Yao Zhengjie, head coach of China's national swimming team, formally announced on Thursday that Zhang would not swim in his pet event in Shanghai, citing "he's out of his best shape".

"He is still far from his top form and is in an adjustment period now. After negotiating with his personal coach, we decided to let him only swim individually in the 200m freestyle in Shanghai. We believe it's the best choice for him," the Beijing Daily quoted Yao as saying during the national squad's first open training session before the worlds.

After winning the 400m freestyle silver medal at the 2008 Beijing Olympics and the 800m freestyle title at the 2009 Rome World Championships, Zhang became the icon of China's men's swimming.

However, tough training and competition schedules in recent years exhausted him, resulting in poor performances at last November's Guangzhou Asian Games, where he only grabbed a 400m freestyle bronze.

Yao said Zhang's priority in Shanghai was just to get back the feeling of battling against top-notch world opponents, while also stating Zhang would compete in the men's 4x100m freestyle relay.

"He has no problem mentally or technically, he just needs to tune up physically. He should constantly take part in elite events to keep the feeling of competition," said Yao, who hailed the 24-year-old as the "spiritual leader" of the team.

"He has a lot of experience at big events. We hope he will be fully prepared before next year's Olympic preliminaries. We are counting on him to lead the relay team at the London Games," said Yao.

Despite an out-of-form Zhang, the Chinese contingent is still eyeing three or four gold medals in its home pool, said Yao, who added Sun Yang now led the country's gold hopes.

"We will try to win three to four gold medals in Shanghai. Sun will be expected to win one or two, hopefully in the men's 800m and 1,500m freestyles," said Yao.

However, 19-year-old Sun, who stunned the world by winning the Guangzhou Asiad's 1,500m freestyle in an Asian record of 14 min, 35.43 sec, only 0.87 sec behind the world record set by Australian great Grant Hackett in 2001, stressed the 400m freestyle title was the one he most wanted.

"I desire the 400m freestyle more than the 800m and 1,500m. Because my toughest opponent, Park Tae-hwan, will be in that event," Sun said.

Park, from South Korea, won the 400m freestyle title at the 2007 worlds to be the first Asian gold medalist in that event and outperformed Sun last year at the Asiad.

On the women's side, 200m butterfly Beijing Olympic champion Liu Zige and runner-up Jiao Liuyang are likely to deliver another gold medal.

Apart from Sun's 400m, 800m and 1,500m freestyles, China has claimed two other world-leading results this year, Liu in the 200m butterfly and promising star Zhao Jing in the 200m backstroke.

"Although we have some world-best results this year, we cannot be assured of winning those events. You never know what will happen in competition," Yao said.

The Shanghai Swimming World Championships will be held for the first time in China from July 16-30 at the Oriental Sports Center.