An extra £19 million has been earmarked to bolster crowd control and public information for the London 2012 Games.
The success of the Queen's Diamond Jubilee, despite the bad weather, plus the on-going torch relay has alerted organisers to the fact that more stewards and crowd flow measures may be needed.
The money will be moved from within the money allocated for the £9.3 billion Olympic project, which is now estimated to come in at £476 million under budget. Olympics minister Hugh Robertson said: "We have only very recently become aware of the scope of the demand for the Olympic Games."
The money will be used to improve crowd management and public information in central London as well as what organisers describe as the last mile. This is plans covering the distance between transport hubs and Games venues.
No figures on how many more stewards would be needed have been released.
Mr Robertson said: "We know exactly how many tickets have been sold and roughly how many people should be in London. Absolutely nobody knows how many people are going to turn up.
"London this summer is going to be the place to have a party. It is a great national event.
"It is very difficult for us to know exactly how many people are going to come across on the train, in the car or on the ferry only for a party."
The estimated £476 million underspend - earmarked for build, infrastructure and regeneration work - will go back to the Treasury.
Mr Robertson described it as a "great success story for UK plc" particularly after the project management of high profile schemes such as the Dome.