The International Olympic [Images] Committee has ordered an investigation into allegations Chinese authorities covered up the age of a double gold medal winning gymnast because she was too young to compete.

He Kexin, who won team gold in artistic gymnastics and an individual title on the asymmetric bars, was registered as being born on January 1, 1992.

There have been persistent media allegations that He had competed in earlier tournaments under a later birthdate, and on Thursday an American computer expert said he had uncovered Chinese state documents that proved she was 14 and not 16.

The caption on a photograph published by Chinese state news agency Xinhua last year referred to "13-year-old He Kexin".

An IOC official said the International Gymnastics Federation (FIG) had been asked to look into "discrepancies" over He's age, but others stressed He had already been cleared to compete.

"Everything that has been received so far shows we have no problem of eligibility for these competitors," said the IOC's sports director Christophe Dubi, adding FIG had asked the Chinese national gymnastics federation to investigate.

IOC spokeswoman Giselle Davies added the organization wanted to clear up the matter 100 percent "and put it to rest".

Gymnasts must turn 16 in the year of the Games to take part, and China's gymnastics coach told a news conference all the team "were in total compliance with the age requirement".

"Since Asian bodies are not the same as Westerners', there have been questions, but there shouldn't be," Huang Yubin said.

China has invested billions in selecting and training its athletes from a young age, an effort rewarded by top spot in the medals table, with 46 golds. This has been seen as a sign China has the sporting prowess to match its rising superpower status.

There has been criticism of the system even from within China, though, with one former Olympic medalist saying many children who fail to make the grade are left without sufficient education or social skills.