Anastasia Lin, a 25-year-old actress crowned Miss World Canada in May, says China is blocking her from travelling to the resort of Sanya for the contest finals on December 19.
"They haven't sent me an invitation letter that I require to apply for a visa," she told AFP.
Other contestants received their letter at the end of October.
Lin said she believes Chinese authorities are acting deliberately, concerned that she will use the event, set to be televised live in China, as a platform to speak out on Beijing's rights record.
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Herself a member of the group that emerged in the 1990s combining Taoist philosophy, meditation and qigong exercises, she testified in July at a US congressional hearing on religious persecution in China.
She told US lawmakers she "wanted to speak for those in China that are beaten, burned and electrocuted for holding to their beliefs; people in prison who eat rotten food with blistered fingers because they dare have convictions."
"When I was crowned Miss World Canada, my father was so proud of me," she said.
"He received hundreds of congratulatory messages. But within a couple days, my father's tone changed. He told me nervously that I must stop my advocacy for human rights in China, or else he would have no choice but to sever contact with me.
"I understand my father was visited by Chinese security agents, who forced him to apply pressure on me in this way.