'Secret device' to control London ceremony teams march

The 205 teams marching at the London Olympics opening ceremony will be controlled with a "secret device" to ensure they do not delay the parade, the International Olympic Committee said.

Several thousand athletes representing 204 nations and the four marching under the Olympic flag will walk at a similar pace with the help of the device, the IOC's Games Executive Director Gilbert Felli said.

IOC member Richard Pound said earlier on Tuesday it was a "shambles" the way athletes took pictures, videos and sent messages during past Games' team parades which delayed the procession.

"We have been working quite hard...and we have very well defined who can participate and have been training how we are going to make it happen," Felli said.

"We will try to accelerate the march and those who play the game and march are not penalised for those who are taking pictures. We have a secret device. You will see, it is secret and I can't tell you now."

Felli said details of the parade procedure would be given to the team heads in a meeting on Wednesday.

At a rehearsal on Monday night, Oscar-winning filmmaker Danny Boyle asked some 30,000 spectators not to post details or photos on social networks of his extravaganza.