A KOREAN television station has broadcast exclusive footage of the Beijing Olympics opening ceremony after a reporter managed to walk into the National Stadium during a rehearsal on Monday.

The ceremony, directed by China's best known film director, Zhang Yimou, was meant to have been under strict security.

Design and production teams and thousands of cast members have been required to sign confidentiality agreements. Breaches of the secrecy agreement are punishable by up to seven years' jail.

Beijing's Olympics spokesman, Sun Weide, said he had only learnt of the footage yesterday and declined to comment. The footage can be seen online.

An employee of Seoul Broadcasting System said one of its Olympics reporters arrived in Beijing on Monday and walked from the International Broadcast Centre to the Birds Nest, as the Olympic stadium is nicknamed. The journalist was able to enter and shoot the footage, which begins with a countdown and thunderous drums.

A giant scroll painting unfurls, revealing a lone rhythmic gymnast. Other highlights include the projection of larger-than-life whales on giant screens that appear to run around the interior lip of the stadium roof and dozens of airborne acrobats dressed as fairies.