Han Zhiguang of the Beijing law firm Gongdao says Falun Gong members in China today number in the tens of millions, the London Telegraph reported Friday.
"We do not know the exact number but one thing is certain: It is expanding," Han told the Telegraph.
Saturday marks the tenth anniversary of a protest in Beijing by 10,000 Falun Gong members that triggered one of the most aggressive suppression campaigns in Chinese history, the newspaper said.
A United Nations report in 2007 said Falun Gong members were the victims in two-thirds of all reported torture cases in China and represent half of the country's prison camp population.
Falun Gong is a mixture of traditional Chinese breathing exercises with philosophy drawn from Buddhism, Taoism and the teachings of its founder, Li Hongzhi.
The Chinese government has labeled it an "evil cult."