Police said they have received a complaint against Rao but no case has been registered in this connection.
The complaint has been filed by M A Qavi, an advocate, they said.
Qavi, in his complaint, alleged Rao had made "derogatory" remarks against the PM during his recent public meetings in the state, the police said.
He sought necessary action against Rao, they said.
Rao, popularly called as KCR, last week maintained he had nothing against Modi and claimed he never used foul language against the PM as alleged by some BJP leaders.