According to the Sunday Mirror, the action has been taken against Coun Sinead Anderson after a photo posted by her husband on X (formerly Twitter) appeared to show her campagining for Reform UK with her husband.
Mr Anderson defected to Reform from the Tories last month.
The photo appears to show Coun Anderson in the background of a group featuring her husband campaigning for Alan Graves, Reform’s candidate for the upcoming East Midlands mayoral election.
If Coun Anderson, who represents Mansfield West at County Hall and is deputy cabinet member for children and families, is found to have campaigned for a rival party, it would be a breach of party rules.
A Conservative Party spokesperson, quoted in the Mirror, said: “Mrs Anderson has been suspended pending investigation.
"The Conservative Party has a robust complaints process in place.
"This process is rightly a confidential one, so that complainants can come forward in confidence."
The issue was initially raised by Broxtowe councillor Steve Carr (Ind), a member of the opposition Independent Alliance at the council, who asked whether Coun Anderson should remain a member of their group with senior responsibilities.
Replying to Coun Carr, a member of the Conservative disciplinary team said: “Thank you for submitting your complaint to the member governance team.
"I can confirm that it has been safely received and is currently being reviewed.”
Coun Carr said, “I thank the Conservative Party for confirming they are looking into this matter.
"Coun Anderson is a senior member of the council and it is only right that is being looked into.
"People have a right to know whether such a senior Conservative, making key decisions over our children’s education is actively supporting Reform and their controversial views.
"The fact that she is actively campaigning against her own council leader is a matter for Ben Bradley.”
When challenged by the Sunday Mirror, Mr Anderson did not deny it was his wife in the picture, instead repeatedly asking: “How do you know it’s her?”
Coun Chris Barnfather (Con), Conservative group business manager at the council, said: “We are aware that Conservative Central Office has received a complaint regarding Coun Anderson from an Independent Alliance councillor.
"The matter is under investigation in accordance with Conservative Party rules, and we as a group are in contact with Conservative Party headquarters pending an outcome, which we hope will be forthcoming expeditiously.”
Your Advertiser has approached Ben Bradley and both Mr and Mrs Anderson for comment.