SYDNEY, Australia (AP) -- Plans to keep the Olympic cauldron under wraps until the Sept. 15 opening ceremony of the Summer Games were ruined Wednesday when images of the towering structure were flashed on Australian TV after construction workers accidentally unveiled it to media.

 Workers were reportedly conducting tests on the structure that will support the Olympic flame during the Sydney games, unaware that a news conference for the National Rugby League football competition was taking place inside Stadium Australia.

 The structure was covered again but not before TV crews and photographers had about five minutes to shoot pictures and video footage.

 The design of the cauldron is usually kept secret until the opening ceremony.

 Sydney 2000 Olympics organizers played down the embarrassing gaffe, releasing a statement which said the structure was a mast that "is part of a very complex multi-dimension construction to support the Olympic flame when it has been lit."

 "It is not the cauldron," organizers said. Sydney organizers have not revealed who will light the Olympic flame or how it will be ignited.