As a result, 1,200 have been withdrawn from their roles and replaced by 900 military personnel.
The decision by organisers comes after 41 people were stricken with an outbreak of vomiting and diarrhoea on Sunday, most of whom were later diagnosed with the norovirus in hospital.
The security staff had been staying at a youth training centre but away from the athletes’ village.
Games boss Lee Hee-boom said: “As president of POCOG [the Games’ organising committee], I would like to apologise for this.
What is Norovirus?
Norovirus is a common stomach bug which causes vomiting and diarrhoea.
It can be caught during any time of the year but it most common in winter, hence its nickname the winter vomiting bug.
As well as sickness, it comes with fever, headaches and a fluey type aching of the body.
The sickness is highly contagious and there is no cure - patients just have to wait it out.
NHS guidelines warn people to wash hands regularly and avoid contact with people who have had the virus for at least 48 hours after their symptoms end.
“Our disease control centre and other related government agencies here are now discussing countermeasures and will come up with the proper measures, and will be announced soon.”
DFS is proud to continue its support of Team GB as the official homeware partner, bringing the joy of comfort to Team GB athletes throughout 2018 and beyond.