China achieved table tennis perfection at the last Olympics, sweeping both singles podiums and winning the team titles, but a rule change has given at least a glimmer of hope to its rivals in London.

Since the sport joined the Olympic program in 1988, China has exerted an iron grip - taking 20 of the 24 available golds, including all four at Atlanta 1996 and Sydney 2000.

But it took its dominance to a new level in front of home fans in Beijing four years ago, winning all six medals on offer in the men's and women's singles, plus gold in both team events.

China's power -demonstrated yet again by its men's and women's titles at the world team championships in Germany this year - has long led to concerns over the sport's public appeal.

But in London, there will be at least two non-Chinese paddlers on the podium, after each country was limited to just two singles entrants. There are also men's and women's team events at the ExCel venue in London's Docklands.

International Table Tennis Federation president Adham Sharara said the new rules will boost other countries' medal hopes - and he called on China's put-upon rivals to step up.

"The Chinese teams do not have a weak link," Sharara said, according to the Xinhua News Agency.

"If you take away any of the team members, they remain very strong. As a matter of fact, they could even enter two teams and maybe win a gold and a silver medal.

"My message to other teams like Germany and France in Europe, Japan and (South) Korea in Asia, is to really think about how they can challenge the Chinese to make it a more interesting contest between the Chinese and the other nations," he said.

Sharara said the new rules guaranteed a wider spread of medals - although he admitted they were "unfortunate" for the excellent Chinese.

"The new rule is unfortunate for the Chinese because they have the three best athletes for sure," Sharara said. "They will now only be competing for two medals instead of three (in the singles events).

"It gives an opening and chance to the rest of the world. This is their chance to try and get a medal. So they should all be motivated and compete."

Underlining China's supremacy, as of June it boasted the world's top five men and top four women. Men's No 1 Zhang Jike enters the singles in London along with Wang Hao, while Ma Long will join for the men's team event.

China's strength in depth is so impressive that three-time gold medalist Ma Lin, the reigning singles champion, missed out.

Germany's Timo Boll, ranked sixth and part of the team that took silver in Beijing, is the only non-Asian in the men's or women's top 10s.

On the women's side, Chinese world champion Ding Ning topped the rankings in June. Li Xiaoxia will also play singles and Guo Yue is included for the women's team competition.

Kasumi Ishikawa of Japan was the highest-ranked non-Chinese, at No 5, with the Singapore duo of Wang Yuegu and Feng Tianwei, part of the women's team that took silver behind China in Beijing, also in the top 10.

Since 1988 there have been only four non-Chinese golds - three for South Korea and one for Sweden's Jan-Ove Waldner, who won the men's singles in 1992 and remains the only non-Asian gold medalist.

There will be other nations on the podium in the singles competitions in London - but expect the medal table to be mostly red.