The police resorted to batons when a water canon and teargas failed to disperse the Congress demonstrators near the Lower PMG close to the assembly building, police sources said.
The demonstrators fought a pitched battle for three hours, trying to break a barricade and threw stones at the police, the sources said.
Director General of Police Prakash Mishra claimed that nearly 60 policemen were injured in stone-throwing and violence by the rallyists but was unable to give the exact number of demonstrators who sustained injuries.
The DGP said though the police was prepared to handle the situation, "organised hooliganism" was not expected from the demonstrators.
Congress leaders including Soumya Ranjan Patnaik, however, alleged that policemen jumped the barricade and beat up party workers as their meeting was in progress.
Hospital and Congress sources said that over 50 civilians were injured in the police action.
Also among the injured were Deputy Commissioner of Police Nitinjeet Singh, Orissa Congress unit chief President Niranjan Patnaik and his senior party colleagues Soumya Ranjan Patnaik and Tara Prasad Bahinipati, police sources said.
The condition of two police personnel, including that of a woman constable, was serious, they said.
The injured were admitted to the Capital Hospital and other private hospitals in the state capital.