The pests have infested 10 South Colonnade, a major government building, and staff have now been advised to work remotely for two weeks.
The infestation was first reported by The Mirror, who revealed last week that the insects had been found on one floor of the government building.
Initial signs of an infestation were found on the fourth floor of the building, sparking alarm around the office.
Since then, the problem has spread to other parts of the office, including the 10th floor that houses the Medicines and Healthcare Products Regulatory Agency (MHRA).
The staff from this governmental agency have been “strongly advised” to avoid entering the building for two weeks.
It has been reported that the Government Property Agency (GPA) has a plan to eliminate the pests, but it is likely to take several weeks.
Workers were warned that, although not dangerous, bed bugs can be uncomfortable, and hard to get rid of, once they are established in an area.
All staff were advised to wash their office clothes at high temperatures to help control the spread of the pests.
Staff were also advised that bed bugs are often found in soft furnishings within offices.
There have been investigations into other offices used by the MHRA in South Mimms, Hertfordshire, and employees have been told not to travel between the two sites to control the infestation.
The problem is causing widespread concern, given fears of a surge in bed bug infestations throughout the UK.
A similar situation unfolded in Paris, affecting schools, transport systems, and hospitals.
The infested building has been home to thousands of civil servants since the government acquired it in 2016.
The facility formerly belonged to Barclays Bank and currently hosts bodies like the UK Health Security Agency (UKHSA).
Garry Graham, Deputy General Secretary of the civil servant representative union, Prospect, said: “This may seem like a trivial matter but for anyone who has had bedbugs they will know the deep and lasting irritation and inconvenience an infestation can cause.
“Any employer must take this seriously, health and safety is not just about danger to life.”
Mr Graham said that the union has urgently raised the issue with the Government Property Agency to address the current infestation.