Met Assistant Commissioner Chris Allison, Olympic security coordinator, said there were no plans to draw on the military, beyond certain niche demands, despite severe spending cuts across the nation's police forces.
Chief constables have seen their budgets cut by about 20% as the coalition government attempts to rein in a record budget deficit approaching 11% of national output.
Allison said forces, which could be called upon to provide special services for the Olympics, such as firearms officers, mounted police, protection and search officers, have been asked to postpone any potential cuts in these areas until after the Games.
Security inside Olympic venues will be the responsibility of LOCOG, the body in charge of staging the Games, which will work alongside the police.
Private security firms will use X-ray machines and carry out searches "much like you would see at an airport," Allison said.
"As you get to the venues clearly you will have to go through a search and secure regime," he told reporters.
"It will look like you would expect. Sadly, as a society we've been having to do deal with the impact of terrorism for many years," he said.
Britain has been a terrorist target for years, and its role in Iraq and Afghanistan, as a leading US ally, has increased the threat posed by Islamic militants.
In July 2005, the day after London was awarded the Games, four young British Islamists killed 52 commuters in suicide bomb attacks on the capital's transport network.
The armed forces could provide niche capabilities, such as Royal Navy boats on waterways, but the military would not be seen on the streets.
"The military don't have the expertise of working on the streets within the UK," Allison told Reuters.
"We work with the consent of the community. Generally, they do a very different sort of operation. We've got the capacity as a service at the moment to deliver a policing operation."
Last month, Policing Minister Nick Herbert said he expected the Olympic security budget to fall from a previous commitment of 600 million pounds to an estimated 475 million pounds through savings, though the full amount would be available if required.
Allison said they were "well under" the 600 million pounds budget, but estimates were changing on a daily basis and securing the Games "was not going to be easy".
(EurActiv with Reuters.)