Gao Zhisheng has been under house arrest since 2014 after serving a three-year prison term on subversion-related charges -- a sentence which sparked an international outcry.

Daughter Grace Gao said the 52-year-old was about to publish a book written in custody and was ready to accept the consequences.

"He told us we (the family) should be prepared. To him he is physically and mentally prepared," the 23-year-old told a press conference.

Gao has indicated he is determined to sacrifice his freedom despite being separated from his family, she said, bursting into tears.

"He's determined he is not going to leave China... for things he thinks are right to do," Grace Gao said.

"He is putting his family aside... he thinks there are things bigger than ourselves."

Gao's wife Geng He fled to the United States in 2009 with Grace and their other child.

The wide-ranging book discusses the physical abuse Gao endured under detention, his faith in God and his belief that the Communist Party could collapse next year.

It has been brought out by a Taiwanese publisher and will go on sale there this week. But the publisher is still looking for a distributor in Hong Kong, said pro-democracy lawmaker Albert Ho.

The dissident lives in an isolated village in Shaanxi province. Ho, a friend of Gao, would not say how the manuscript was delivered to the publisher.

Gao fell foul of Chinese authorities by championing the rights of vulnerable people including underground Christians, aggrieved miners and members of the banned Falungong spiritual movement.

He was convicted in 2006 of "subversion of state power" and given a three-year suspended prison sentence.

State media said in 2011 that he had been ordered to serve the sentence after a Beijing court ruled he had violated the terms of his probation.

The decision was criticised by the United Nations, the United States, the European Union and rights groups such as Amnesty International.

Upon his 2014 release, his family said he had suffered abuse in prison and malnutrition that led to severe tooth damage.

Grace said her father was still living in "difficult" conditions and not receiving proper care.

China imprisons a number of high-profile critics including Liu Xiaobo, the writer and democracy advocate who won the Nobel Peace Prize in 2010.