A 72-year-old Chinese journalist jailed for "leaking state secrets" in a case that drew international condemnation spoke out for the first time on Thursday since her release on medical parole.

Veteran reporter Gao Yu was imprisoned last year for allegedly leaking a directive by the ruling Communist Party, warning against the "dangers" of multiparty democracy. She spent 18 months in custody before conviction.

The septuagenarian, who suffers from heart problems, had her seven-year sentence reduced to five in November, and was granted parole on medical grounds.

The official Xinhua news agency said at the time the sentence reduction was made because Gao "expressed guilt" during an appeal hearing held in secret.

But the journalist dismissed any possible admission of guilt as a "joke" when contacted by AFP at her home on Thursday, adding that authorities had prevented her from travelling to Germany for medical treatment.

She said her actions were part of a "Chinese style plea-bargain", and that officials had warned her against discussing her case in public as a condition of her parole.

Gao said her decision to talk to journalists was prompted by a physical assault on her son by urban management officials in Beijing who tried to demolish a section of her apartment in Beijing.

AFP could not verify the details of the incident. Pictures posted online appeared to show a large number of police surrounding her home.

Gao, a former freelance journalist, also said she had trouble paying medical bills since her release as she had no source of income.

She previously wrote for Berlin-based Deutsche Welle, and Germany has said it raised her case with Chinese officials.

"Germany gave me a visa and bought me plane tickets, but (officials) told me I am on medical parole and cannot leave the country," she said.

Police in Beijing could not immediately be reached for comment.

-'Document number 9'-

A former winner of UNESCO's World Press Freedom Prize, Gao has been a consistent critic of the Communist Party's authoritarian policies.

She was imprisoned following the government crackdown on student protests in Tiananmen Square in 1989, and again for six years in the 1990s also on a charge of "leaking state secrets".

A Beijing court said in April last year she had leaked "Document Number 9", an internal Communist Party memo that was widely circulated online.

Dated 2013, the document denounces "universal" definitions of human rights and criticism of the party's historical record, according to copies circulated.

Gao's jailing was condemned by human rights groups, while Washington called for her immediate release and the EU demanded Beijing review her trial.

China's President Xi Jinping has overseen a crackdown on dissent since coming to power in 2012, with hundreds of lawyers, activists and academics detained and dozens jailed.

France-based Reporters Without Borders ranked China 176th out of 180 countries in its 2015 Press Freedom Index.

Gao told AFP: "Although I never thought that I should face prison, I have no option but to go along with their rules."