Gymnasts may well dazzle the judges with their skill, grace and power at the Beijing Olympics but none will receive the coveted "perfect 10" score awarded at past Games.

Beijing is the first Olympics staged under a new scoring system that scraps the perfect 10 first awarded to Romania's Nadia Comaneci in Montreal in 1976 in what is still the defining moment for gymnastics at the Olympics.

Instead, gymnasts receive two scores - one an open-ended mark measuring the difficulty of the routine, the other a mark out of 10 for how well it was executed.

US gymnast Morgan Hamm said he regretted the change and believed it would need to be carefully explained to television viewers who only watch gymnastics once every four years at the Olympics.

"It was something that I grew up with and when I think of 10.0, it's perfection," he said.

"It was disappointing when they changed the system. It would be nice if it was still here but the sport keeps evolving."

The new system means a good score at an elite level meeting ranges from about 15-17 but even an insider like Hamm said he struggled to understand it initially.

"When I started seeing 15s and 16s from people, it was a little bit hard to know what was a good score," he said. "It's going to be important for the commentators to stress how they're getting the scores and what's a good score."

The change was brought in after two scoring controversies at the Athens Olympics, one involving Hamm's twin brother Paul, who won the all around gold medal after judges accidentally underscored his South Korean opponent.

In the other Athens controversy, a low score awarded to Russian Alexei Nemov on the high bar caused uproar among the crowd, forcing competition to be suspended for 10 minutes, before two judges upped their scores without explanation.