Beijing's Publicity Department, which is in charge of propaganda and ideological control, issued the order last week, a mainland source told the South China Morning Post.
The paper said the move reflected official concern over the growing influence academics are exercising in the public sphere.
Wang Yi, a law professor at Chengdu University, and nationally published columnist, said the idea of public intellectuals threatened governmental authority in the one-party state.
"Another concept corresponding to the notion of public intellectual is public politics, which is inevitably about dissent and even the forming of opposition forces," the newspaper quoted Wang as saying.
Wang said public intellectuals required moral courage, professional expertise and the willingness to act. But years of experience showed that acting out of a sense of social responsibility and conscience carried risks, he said.