China's State security agency said on Wednesday that it had deported Australian national Cheng Lei after she served a full sentence for illegally providing Chinese State security secrets abroad.

The news release was disclosed by the country's Ministry of State Security via its WeChat account.

Cheng, 48, was an employee of Beijing-based Chinese media platform China Global Television Network.

In May 2020, she was found to have been co-opted by an overseas institution, violated the confidentiality clause signed with her employer, and illegally provided Chinese State secrets she had known at work to the overseas institution through her mobile phone, according to the news release.

The security agency in Beijing detained Cheng in August 2020 for allegedly sharing Chinese secrets with another country, and then Cheng pleaded guilty to her offense, it said.

After a trial at the Beijing No 2 Intermediate People's Court, Cheng was sentenced to two years and 11 months for the crime of illegally supplying Chinese State secrets abroad, plus deportation. She did not appeal to a higher court, it said.

It added that Chinese judicial authorities solved the case in line with the law, with full guarantee of Cheng's legitimate rights during the process.

Chinese Foreign Ministry spokesperson Wang Wenbin said on Wednesday that the Chinese judicial authorities have also respected and implemented the consular rights of the Australian side, such as those on visitation and notification.

Responding to a question over Cheng's trial at a routine news conference in March last year, Wang cited the Chinese Criminal Procedure Law as saying that cases involving State secrets should not be heard in public, stressing that it is lawful and beyond reproach for the trial of Cheng to be held behind closed doors as it involves State secrets.

During that news conference, he also emphasized that China is a country that operates under the rule of law, and judicial organs handle cases strictly in accordance with the law, with full protection of the litigation rights to relevant personnel.

Relevant parties should earnestly respect China's judicial sovereignty and refrain from interfering in any form with China's judicial organs, he added.

Cheng was born in China and later emigrated to Australia with her parents.