The Chinese embassy has raised its "great concern" with the Australian government that hundreds of Chinese PhD students hoping to start their studies here have endured long visa delays.

"The reasons for the delays have not been clearly explained," an embassy spokesman told The Sydney Morning Herald and The Age via email. "We have raised this issue with relevant Australian agencies. We will continue to do that and hope it could be properly addressed."

Chinese researchers are frustrated and angry that their visas are delayed. Credit:Peter Braig

Australian experts have warned about the risk of Chinese researchers' work here being applied in ways that are contrary to Australia's interests when the researchers return home to China, and the United States is increasingly competing with China in the academic sphere.

Against that backdrop a group of about 230 Chinese students, who have connected on social media platforms, said they had been waiting months — and in some cases more than a year — longer than normal for a visa.