Security tsar Meng Jianzhu has criticised excessive interference by officials in court proceedings - a practice so rampant that judges frequently receive notes at the bench telling them how to rule.
Meng, the newly appointed secretary of the Central Politics and Legal Affairs Committee, attacked the "passing of paper slips" at a video conference with top law-and-order officials on Monday, sources said.
Such notes are usually passed by members of lower-level politics and legal affairs committees based in the courts.
"Meng criticised the old system in which the party's committee always gives concrete instructions to the courts to tell them how to rule on individual cases," said one participant who declined to be named.
The source had often witnessed committee members passing notes to judges.
The remarks, in which Meng also announced an eventual end to the "re-education through forced labour" system, were not reported by state media.
The committees have been condemned by legal experts as a source of obstruction of justice, especially in regard to political lawsuits. The committees, which have overriding authority in courts, exist in all jurisdictions.
"The existence of the committees is a violation of the constitution by damaging judicial independence," said Hu Jinguang, a constitutional law professor at Renmin University.
"Laws are only as good as the party authorities who allow them to be enforced."
Professor Tong Zhiwei, of the East China University of Politics, said intervention by the committees increased in the last five years under Meng's predecessor, Zhou Yongkang . "Meng's comments show the new generation of leadership is willing to reflect on and reform the existence of the committee system, which goes against the legal system and undermines the law," said Tong, who advocates the abolition of lower-level committees.
The status of the Central Politics and Legal Affairs Committee was diminished with Zhou's retirement last month. While Zhou was a member of the all-powerful Politburo Standing Committee, Meng sits on the lesser 25-member Politburo. Experts believe that ending the passing of slips and re-education through labour would accomplish little.
Hu said it was almost impossible for the committee to give up its influence on court verdicts as it had become a well-established practice and was one of the easiest ways for party authorities to retain control. "To weaken the power of the committees doesn't mean to weaken the influence of the party on court and political decisions," he said.