Buddhists from more than 30 countries are in China for the World Buddhist Forum - communist China's first international religious gathering.
There are about 100 million Buddhists in China
Hundreds of monks and scholars are visiting the eastern city of Hangzhou, but Buddhist spiritual leader, the Dalai Lama, has not been invited.
China regards the exiled Tibetan leader as a separatist.
It has made its choice of Panchen Lama - Tibet's second most important figure - the figurehead of the conference.
But according to Reuters news agency he appeared to be shunned by delegates.
Fellow Buddhists made no attempt to greet Gyaltsen Norbu during greeting ceremonies ahead of the conference on Wednesday, the agency reported.
The Dalai Lama has nominated his own Panchen Lama, who has disappeared and is believed to be under house arrest.
China appointed Gyaltsen Norbu in his place in 1995.
China has about 100 million Buddhists.
The officially atheist communist party keeps a tight rein on all religious activities, fearing a possible challenge to its authority, says the BBC's Dan Griffiths in the Chinese capital.
Gyaltsen Norbu made a rare public appearance
Worship is only allowed through state-run organisations. Many monks and nuns have been jailed for their loyalty to the Dalai Lama, and followers of underground Christian churches have also received lengthy prison sentences.
China said it did not want the Dalai Lama to "disharmonise" the forum, which opens on Thursday and runs until Sunday.
"The Dalai Lama is not only a religious figure, but is also a long-time stubborn secessionist who has tried to split his Chinese motherland and break the unity among different ethnic groups," said Qi Xiaofei, vice-director of the state administration for religious affairs.
But China is trying to thaw relations with religious establishments, including the Vatican, our correspondent says.
Beijing is also hoping that the meeting in Hangzhou will ease US criticism of China's religious freedoms ahead of President Hu Jintao's visit to Washington next week, he adds.