Troops drafted in to protect London 2012 venues after the G4S fiasco make up 50% of the security personnel at the Olympic Park, it has been revealed.
Games organisers were forced to turn to the military when the contractor admitted it did not have enough staff to fulfil its contract.
Some 4,700 service personnel are now plugging the gaps - half the total of security staff at the venue in Stratford, east London.
Paul Deighton, chief executive of Locog, said: "Yesterday, in terms of the different groups running security, we had about 50% military, 40% G4S... and about 10% volunteers."
He said there have been "absolutely no issues" for people coming into the park through through aeas where G4S was contracted to conduct physical searches and operate X-ray machines.
"What we've done in terms of training, capacity and management of that... has been very effective," he added.
His comments came as it emerged soldiers guarding Olympic sites in London were being housed in accommodation branded "absolutely disgusting".
The criticism has come from the approximately 500 personnel from 1st Battalion The Princess of Wales's Royal Regiment (1PWRR) who are being put up at Tobacco Dock near Tower Bridge.
Fiona Mason, from Fair Oak in Hampshire, whose son Paul, 21, is a member of the regiment, told the Southern Daily Echo the men were "treated better in the desert".
The total number of military personnel involved in Olympics security is now more than 18,000, with 11,000 helping secure Games venues and the rest working in specialist roles.
G4S chief executive Nick Buckles has faced calls to resign from his £830,000-a-year job after the firm's failure to suppy enough guards.
The company is set to lose up to £50m on the £284m contract, equivalent to 10% of its annual £500m profit.