SYDNEY (REUTERS) - Australia has revoked the visas of two visiting Chinese academics in an apparent escalation of tension between the countries, which has seen each accuse the other of inappropriate treatment of journalists.

Professor Chen Hong, a professor of Australian Studies at East China Normal University in Shanghai, said in an e-mail to Reuters that he had received a letter from Australia's Home Affairs Department cancelling his visa.

The letter said he had been deemed by security body ASIO to pose a threat to national security.

"I absolutely refuse to accept this assessment, and believe a gross mistake has been made regarding my relationship with Australia," Prof Chen said in the e-mail.

"I have done nothing and will do nothing to act as a risk to Australia's security."

Australian Broadcasting Corp reported that another scholar, Mr Li Jianjun, had received a similar letter. Mr Li could not immediately be reached for comment.

The move intensifies a round of recriminations between the countries that has involved reports of Australian journalists in China being questioned by police, prompting them to leave the country, and of Australian authorities raiding the homes of Chinese media representatives there.

A spokesman for Australian National University, where Mr Li was named this year as a visiting scholar, said he finished his appointment there in February.

The Department of Home Affairs and ASIO were also not immediately available for comment.

Australia has a tense diplomatic relationship with China, which worsened this year after Beijing vowed trade reprisals and said it was angered by Australia's call for an international inquiry into the source of the coronavirus pandemic.