Announced in meetings in recent weeks but not published, the restrictions target residents of Lhasa, the often tense political and religious center of Tibet, the London-based Tibet Information Network said.
In the suburban Lhasa county of Lingzhi, police have searched homes, hunting for private Buddhist shrines, pictures of the Dalai Lama, and incense burners, the group said, citing sources it did not identify. One of them reported that the raids typically occur around 2 a.m.
The restrictions expand a four-year-old campaign to get Tibet's overwhelmingly Buddhist people to reject the Dalai Lama, their temporal and spiritual leader who remains widely popular 50 years after Chinese troops entered Tibet and 41 years after he fled to India.
Chinese leaders have previously prohibited members of the officially atheistic Communist Party from taking part in religion. In 1996, they began purging the clergy of Dalai Lama supporters and banned his photos from temples, monasteries, and public places. Some private homes were reportedly searched as well.
But the new limits apply to all Lhasa residents, and particular attention is being paid to Tibetans working in private businesses or for foreigners, the Tibet Information Network said.
Officials threatened students with expulsion if they visited monasteries or temples, the group said. It noted that students often visit holy sites to pray for success in the exams that end the school year.
Worried about the growing appeal of religion across China, Chinese leaders have waged a year-old campaign against what they label superstition. A government policy paper on Tibet issued in June called certain traditional beliefs hindrances to building a modern civilization.
China's unease about its hold on Tibet becomes most evident around sensitive anniversaries. The monitoring group said prohibitions on celebrating the Dalai Lama's 65th birthday on July 6 were strictly enforced.