Concerns over the future of the Athens Olympics are mounting after it emerged that Lloyd's underwriters baulked at the £500m cancellation cover that the organiser is looking for.

It is feared that the stadium and other facilities will not be ready in time for August and so the Athens 2004 Organising Committee (ATHOC) is looking to place £500m cancellation cover through its broker Marsh.

Marsh is understood to be attempting to place the cover, but has found the Lloyd's market unwilling to take on the risk. It is understood that Marsh will now have to look at overseas markets.

One Lloyd's underwriter said: "The Olympic organisation may find it difficult to find the cover they need because so many insurers are withdrawing from contingency business."

It is understood that Lloyd's underwriters have shied away from insuring the games against cancellation due to problems relating to unfinished stadiums, as well as potential terrorism and marine risks.

"Perhaps the venues are not as complete as they would like," said the underwriter.

"But Greece has got everything - you're in an earthquake zone, and you've also got the marine, cargo and terrorism risks."

A Marsh spokesman declined to comment, but a leading event cancellation insurer said that the broker had so far failed to obtain the event cancellation cover for ATHOC.

Experts estimate that an event cancellation policy for ATHOC would provide between £300m and £500m of cover.

Such a policy could include cover for: non-appearance of major teams; boycott; cancellation; abandonment and postponement; loss of profit and loss of ticket revenue.

It is understood that ATHOC originally decided against cancellation cover but later performed a

U-turn and began looking for cover.

ATHOC was unavailable for comment as Insurance Times went to press.