THE girl who starred at the Olympic opening ceremony was miming and only put on stage because the real singer was not considered attractive enough, the musical director said.

Pigtailed Lin Miaoke was selected to appear because of her cute appearance and had not sung a note, Chen Qigang, the general music designer of the ceremony, said in an interview with a state broadcaster.

Photographs of Lin in a bright red party dress were published in newspapers and websites all over the world and the official China Daily hailed her as a rising star on Tuesday.

But Chen said the girl whose voice was actually heard by the 91,000 capacity crowd at the main Olympic stadium was in fact seven-year-old Yang Peiyi, who has a chubby face and uneven teeth.

"The reason why little Yang was not chosen to appear was because we wanted to project the right image, we were thinking about what was best for the nation," Chen said in the interview that appeared briefly on the popular news website Sina.com on Tuesday before it was wiped from the Internet.

Lin was seen to perform the patriotic song Ode to the Motherland as China's national flag was carried into the stadium, a key moment in the three hour opening ceremony.

"The reason was for the national interest. The child on camera should be flawless in image, internal feelings, and expression," he said.

"Lin Miaoke is excellent in those aspects. But in terms of voice, Yang Peiyi is perfect, each member of our team agreed."

There has been no official word from BOCOG on the story that the little girl in red who starred in it was miming - and only put on stage because the real singer wasn't considered attractive enough.

Meanwhile, Olympic organisers have conceded that television images of the giant footprints of fire in the opening ceremony were pre-recorded and cut into live footage of the spectacular because of poor visibility in the city.

BOCOG vice president Wang Wei said the dramatic footprints of fire that appeared to "step" from Tiananmen Square to the northern Beijing Olympic district were pre-prepared.

However, he insisted the fireworks that created the 29 steps had actually exploded on the night and most of the television images used of the ceremony were genuine.

"At the opening ceremony there were actual footprints fired from the south to the north of the city," Wang told reporters.

"However, because of the poor visibility of the night some previously recorded foots may have been used."

Reports in the Beijing Times said that the moment had been expensively faked by a production company, who created a computer-generated version of the stepping fireworks.

The company, Crystal fireworks, used effects to capture the shakiness of filming from a helicopter and even the blurring effect of haze, the newspaper reported, citing the head of the visual effects team for the ceremony.

"Most of the audience thought it was filmed live - so that was mission accomplished," Gao Xiaolong told the paper.