It is hard to predict Chinese athletes' performance at next year's Beijing Olympic Games as there are many challenges ahead during its preparation, said a Chinese sport official here on Wednesday.

Cui Dalin, vice president of the State General Administration of Sports, said the public may overestimate Chinese athletes' ability to win gold medals because they consider host athletes should have an edge over others on home soil. He refused to make any prediction for China's gold medal count.

"The general public have very high expectations on us but actually our athletes will be faced with extremely fierce competition and the situation is pretty severe," said Cui.

"We think the United States and Russia can be called the 'first group' and China will try to keep its leading position in the 'second group'," he said.

He first gave reporters a batch of statistics comparing gold medals and medals won by the United States, Russia and China at Athens Olympics four years ago and major world championships in recent years.

"Although we had 32 gold in Athens Olympics but in terms of the total of medals, we were 40 fewer than the United States, 29 fewer than Russia," he said. "That means those two countries are better than China in overall strength."

The United States pulled off 35 gold, 39 silver and 29 bronze to total 103 medals in Athens while second-placed China had 32, 17 and 14 respectively. Russia followed behind with 27, 27 and 38.

"Another problem is that we have already bought out full potential in such advantageous events as diving, table tennis, badminton, gymnastics, shooting and weightlifting in Athens. There is little room to improve on the results in Beijing," he said. China clinched six out of eight diving titles while table tennis had three of four. Other events also saw Chinese athletes make gold medal haul in Athens.

"Everyone thinks that host athletes enjoy huge support but it can be a pressure too, especially when our advantageous events are those which need steadiness and delicate techniques," he said.

China has booked about 450 qualifications in Beijing Olympics which kicks off on August 8 next year. There are 1,500 athletes in 55 national teams training for the Games, Cui said.