MPs today expressed concern that the London 2012 Olympics may go over budget and said it was "staggering" that initial estimates about security costs were so wrong.
The Public Accounts Committee's report into the London Olympics also raised concerns about the legacy of the Games and warned that the Olympic Stadium must not become a white elephant.
The Government however have continued to insist they are confident the Games will come in under budget.
Margaret Hodge, chair of the Public Accounts Committee, said: "The venues and infrastructure of the London Olympic Games are on track to be delivered on time and within budget. The Olympic Delivery Authority's management of the building programme has been exemplary.
"However, the £9.3billion public sector funding package is close to being used up and we are concerned about whether the running of the Games will be held within budget.
"Taking into account costs outside the package, the full cost to the public of the Games and legacy projects is already heading for around £11billion.
"We are particularly concerned about the significant increases in the security bill. LOCOG (the London organising committee) now needs more than twice the number of security guards it originally estimated and the costs have roughly doubled."