Sky News understands that nine out of 12 police forces have been drafted in to help the embattled firm ensure the Games are kept secure.
The forces providing additional personnel include Strathclyde, West Midlands, Thames Valley, Greater Manchester and Dorset.
Sky News home affairs correspondent Mark White said: "The police say at this stage they have deployed hundreds of officers rather than thousands, but that could change in the coming days as more Olympic venues go into security lockdown."
"The need for extra officers will depend on whether G4S can meet its security commitment in the coming days and whether the military can deploy to those venues in time."
Assistant Commissioner Chris Allison, the Police National Olympic Security Coordinator, told Sky News: "Whilst some of the activity police officers are undertaking was not anticipated, plans were put in place to allow us to do this.
"Forces are making sure they make the best use of their resources locally to do all they can to minimise the impact on local policing.
"Delivering a safe and secure Games is a priority, but we will not compromise on keeping our local communities safe."
The details emerged after Northumbria Police were called in to help G4S with Olympic football security.
Sky Tyne and Wear discovered that less than 10 G4S guards reported for duty out of an expected 58 staff, as Northumbria Police Federation called the security firm's blunder "shambolic".
Chairman Charlie Munro said: "We are an emergency service and of course we will provide cover. The situation really is shambolic.
"I really think G4S needs to be looked at. They are a very big organisation and they've had long enough to plan for this. It really doesn't fill us with confidence."
A spokesperson for G4S said: "As the games get closer, security is being tightened at venues around the UK, before the full complement of accredited staff have been assigned.
"Some venues are being supported by police in the short-term while the private security workforce is being mobilised.
"This situation is being rectified over the coming days, which should lead to the withdrawal of police from those roles assigned to private security."
The new revelation comes as Home Secretary Theresa May told the Commons about details behind the Olympic security crisis.
"I want to be clear, this was the first time G4S told any minister about not being able to fulfil the contract," Mrs May told Parliament.
"G4S had repeatedly assured us it would overshoot their targets."
Defence minister Andrew Robathan told the Commons that the Olympic security situation was a "debacle".
The crisis has escalated since it was revealed last week that thousands of troops were needed to provide venue security after G4S admitted it may not be able to provide its full complement of 10,400 staff.
Mrs May said 20,000 G4S staff had been vetted and accredited, however the main problem was a shortfall when the company tried to allocate staff among venue.
She confirmed that no member of the armed forces would be out of pocket or losing leave entitlement over the need to deploy and supplement G4S staff.
The G4S share price plunged around 10% during early Monday trading before closing 24.1p down at 254.78p, more than 8.5% on the day.
Meanwhile, newly-appointed chairman John Connolly agreed to meet key City investors to discuss the crisis and its impact on the company.
Embattled CEO Nick Buckles now appears increasingly likely to become a victim of the debacle, which has been estimated to cost the firm £50m.
Some experts, however, expect the damage to be much deeper than the company has calculated and G4S' plans to nearly double its UK Government outsourcing are now under threat.
The company has been advertising for a new HR director, to be paid a six-figure sum, to manage 3,500 staff as they launch "ambitious plans" to reach a turnover of £400m by 2015.
Labour MP Keith Vaz has called into question the firm's role in outsourcing and said the company has "let down" the country.