Xi, regarded as the most powerful Chinese leader in recent decades as he heads the Communist Party of China (CPC), the government and the military warned members not to ask questions "that should not be asked" and told them not to spread gossip about party politics.
The comments were published in the latest book edited by the Central Commission for Discipline Inspection (CCDI) of the CPC which collected previously undisclosed remarks made by Xi since he took over power the leadership in November 2012, the Hong Kong based South China Morning Post reported.
"Some have been keen to poke around and...Ask the things they should not ask... And run after the so-called internal information and spread it in private," Xi said, adding such actions had been rotting and decaying the party, the Post report said.
In the same speech, Xi criticised party officials who failed to report personal problems relating to their health, children and marriages until the problems had become serious.
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The publication of Xi's remarks comes ahead of a CCDI conference from January 12-14.
The party has recently introduced punishments for party members who make inappropriate comments about key policies, vilify party leaders, distort history or who fail to honestly report important personal matters.
Also Xi's remarks that no one will be immune from punishment for corruption is a warning to influential retired leaders or princelings who may be standing in his way, the Post quoted analysts as saying.