An aide to Housing Minister Dominic Raab has been suspended over allegations she met men though a "sugar daddy" website and discussed her work with an undercover reporter.
The Ministry of Housing, Communities and Local Government (MHCLG) is investigating the claims relating to a civil servant at the department.
According to the Daily Mirror the woman boasted of knowing "everything" about Mr Raab and that she knew his "every move".
The employee met twice with an undercover journalist posing as a wealthy businessman, including at a five-star hotel less than a mile from the House of Commons.
At the end of each meeting she was paid £750, the paper said.
The Ministry for Housing, Communities and Local Government (MHCLG) launched the probe amid concerns that the woman's actions could pose a security risk.
There is no suggestion that Mr Raab was aware of the woman's actions.
A spokeswoman for the MHCLG told the Press Association: "We are aware of this allegation against one of our members of staff, and are investigating.
"There is no suggestion that any official information has been disclosed."
It is understood the woman was suspended on Wednesday afternoon pending the outcome of the investigation.
Sources stressed that Mr Raab had no role in appointing the member of staff.
The official allegedly met with men on a controversial site used by younger women known as "sugar babies" and older, wealthy men to arrange liaisons.
According to the paper when asked what her bosses would think of her use of the site she said "I don't care".
In a sign of how much she knew about the minister's daily routine, she revealed he has the same lunch every day from Pret a Manger.
"He has the chicken Caesar and bacon baguette, superfruit pot and the vitamin volcano smoothie every day," she said.
"He is so weird. I get it for him. I go to Pret. That's how I know. It's the Dom Raab Special."