A citizen journalist jailed for her coverage of China's initial response to COVID-19 in Wuhan is close to death after going on hunger strike, her family said, prompting renewed calls from rights groups for her immediate release.

Zhang Zhan, 38, a former lawyer, traveled to Wuhan in February 2020 to report on the chaos at the pandemic's epicenter, questioning authorities' handling of the outbreak in her smartphone videos.

She was detained in May 2020 and sentenced in December to four years in jail for "picking quarrels and provoking trouble" – a charge routinely used to suppress dissent.

She is now severely underweight and "may not live for much longer," her brother Zhang Ju wrote last week on a Twitter account verified by people close to the matter.

Zhang has been on a hunger strike and was force-fed through nasal tubes, her legal team, which did not have information on her current condition, told Agence France-Presse (AFP) earlier this year.

"She may not survive the coming cold winter," Zhang Ju wrote, adding that he had urged his sister in letters to "take care of herself."

"In her heart, it seems there is only God and her beliefs, with no care for anything else."

Zhang Ju's posts sparked fresh calls for his sister's release, with Amnesty International urging the Chinese government Thursday to "release her immediately so that she can end her hunger strike and receive the appropriate medical treatment she desperately needs."

Amnesty campaigner Gwen Lee said in a statement that Zhang's detention was a "shameful attack on human rights."

Someone close to the citizen journalist, who declined to be named, told AFP the family had asked to meet Zhang more than three weeks ago at the Shanghai women's prison where she is being held but had not received a response.

AFP was unable to reach Zhang Ju while Zhang's mother declined to comment. The Shanghai prison also offered no response when approached by AFP.

'Apply pressure'

China's foreign ministry on Friday did not comment on Zhang's condition but dismissed calls from rights groups for her release as "anti-China political manipulation."

"China is a country with rule of law," foreign ministry spokesperson Wang Wenbin said at a regular press conference. "Anyone who breaks the law must be punished in accordance with the law."

Zhang now cannot walk or even raise her head without help, according to Reporters without Borders (RSF).

RSF East Asia Bureau head, Cedric Alviani, said, "International community (must) apply pressure to the Chinese regime and secure Zhang Zhan's immediate release before it is too late."

"She was only performing her duty as a reporter and should never have been detained, not to mention receive a four-year prison sentence."

China has reveled in its success in keeping domestic infections down to a trickle of sporadic outbreaks.

The government has put forward a narrative crediting the Communist Party with returning life almost to normal even as death tolls and infections continue to explode in the rest of the world.

But those who threaten the official version by raising questions about the government's early cover-up and handling of the Wuhan outbreak face the party's wrath.

Zhang is among a group of four citizen journalists – including Chen Qiushi, Fang Bin and Li Zehua – detained after reporting from Wuhan.