Nick Buckles, the firm’s chief executive, will be asked how G4S, the world’s second largest private sector employer, has failed to get enough security guards for Games venues when more than 20,000 have already been accredited.
He will face questions from Labour MP Keith Vaz, chairman of the Commons Home Affairs Select Committee, who accused his firm of letting the country down last week.
Mr Buckles, 51, would be entitled to £20m in pay and benefits if he loses his job over the fiasco which is expected to cause his firm £50m of losses on the high-profile contract.
More than £400m has been wiped off the firm’s value since Wednesday and Home Secretary Theresa May has been forced to appear before MPs twice in the last week over the row.
G4S repeatedly assured ministers it would “overshoot” its recruitment targets and only admitted it would fail last week, she said yesterday.
A further 3,500 troops who were drafted in to close the gap left by G4S have now been joined by officers from eight police forces after security staff failed to turn up at venues.
Mrs May said that despite more than 20,000 security staff being accredited, G4S had problems with scheduling and “getting staff to the venue security tasks”.
Some staff no longer wanted the work, she added.
But Mrs May came under fire from Labour for not knowing how many staff G4S would now provide after the Home Secretary told MPs the “precise balance of the number who will be provided will become clear over the next few days”.
But she denied the firm had “deliberately deceived” the Government.
A total of 3,500 troops, many of whom will be billeted at Tobacco Dock near Wapping, east London, were brought in to make up the shortfall, boosting the number of servicemen and women involved in Games security to 17,000 last week.
Hundreds of officers from eight forces have now also been drafted in to fill gaps.
Venue security was being tightened “before the full complement of accredited staff have been assigned”, a G4S spokesman said.
“This situation is being rectified over the coming days, which should lead to the withdrawal of police officers from those roles assigned to private security.”
The forces involved so far are Dorset, Hertfordshire, Northumbria, South Wales, Strathclyde, West Midlands, Thames Valley and Greater Manchester.
Paul Murphy, chairman of Greater Manchester Police Authority, said just 20 of the expected 58 G4S staff turned up at the main Olympic team hotel in Worsley on Saturday to help conduct a “lock-down” of the building.
Mr Murphy told BBC Radio 4’s PM: “Greater Manchester Police had to step in and ensure that the site was properly locked down.
“We have had to use officers and staff on rest days. We have had 28 Pcs and four sergeants into that area, at a cost of £30,000 a day.”
The Police Federation, which represents rank-and-file officers, said the situation was “chaos, absolute chaos”.
Ian Edwards, chairman of the West Midlands branch, said the force is providing 150 officers per day to cover a hotel in Warwickshire where footballers are staying.
“The worst-case scenario is that we end up having to find another 200 officers for the security at the City of Coventry stadium, and we’ve yet to find out what the shortfall is in Birmingham,” he said.
“It’s chaos, absolute chaos.
“You shouldn’t lose your local police officer because of the Olympics. Communities are suffering because a private company has failed to deliver on a contract.”
A confidential report by HM Inspectorate of Constabulary (HMIC) warned about concerns over security 10 months ago, leading Games organisers Locog to increase the number of security guards to be supplied by G4S from 2,000 to 10,400 while the value of the contract more than trebled from £86m to £284m.