The chairman of the London 2012 Organizing Committee Sebastian Coe said Sunday that a recruitment shortfall by private security firm G4S would not jeopardise the safety of the Olympic games.
G4S chief executive Nick Buckles on Saturday said he was "very sorry" that 3,500 troops had to be drafted in just two weeks before the Games, after the firm admitted it could not provide the total 10,000 guards it had pledged.
"G4S expected people to materialise and when they didn't... we moved very quickly to fill that gap," Coe told BBC Radio 5 live. "This is not about numbers, this is about the mix.
"I'm in the Olympic Park every day, we've got 4,000 trained G4S personnel in the park and they've been there for some years and they've been doing a spectacularly good job," he added.
The former Olympic gold medalist promised a "prudent and judicious plan" was in place.
Culture Secretary Jeremy Hunt said the government had the contingency plan drawn up "for many months".
"We are just very lucky to have fantastic armed services who can come when we need them and they will do a brilliant job," he told BBC.
Speaking publicly for the first time since details of the fiasco emerged Wednesday, Buckles confirmed that G4S, one of the world's largest security firms, faces losses of up to £50 million ($78 million, 64 million euros) over the blunder.
"We accept that we underestimated the task of supplying staff for the Olympics. We deeply regret that," he told BBC radio.
"It's only when you get closer and closer to the Games that you realise that the number isn't as high as you expect," he said.
Buckles apologised directly to the troops involved, some of whom were due to go on leave after tours in Afghanistan.
G4S was originally contracted to provide the Games with 2,000 personnel for £86 million, but this was increased in December to 10,400 while the value of the contract more than trebled.
On Thursday, the defence ministry announced that G4S had been unable to recruit enough guards and that 3,500 soldiers would step in to fill the shortfall, bringing the total number of troops involved in the Games to 17,000.
Britain is deploying a total force of 40,000 troops, police, guards and volunteers for the Games, in its biggest ever peacetime security operation.