High numbers of Chinese students at Australian universities have created an environment of self-censorship with lecturers avoiding criticism of Beijing and Chinese students staying silent in fear of harassment, Human Rights Watch said.

Some parents in mainland China had been questioned by Chinese police about the activities of students in Australia and Hong Kong police had questioned a returning student about pro-democracy activities, the group said in a report released on Wednesday.

Self-censorship has worsened as universities have adopted online courses during the Covid-19 pandemic, with Chinese students joining class from behind China's "Great Firewall" system of internet censorship, the group said.

The trend compromised the academic freedom of all students in the class, the report's author, Sophie McNeill, told Reuters.

"It erodes Australia's academic freedom," she said.

In one example...