Former chairs of the Hong Kong Bar Association have warned that the nationwide arrest and detention of human rights lawyers in China could have a ‘chilling effect’ on the country’s legal profession.

A petition published on last week by 13 former heads of the assocation and representatives of the region's legal profession, expressed concern about the arrests and denounced the harassment against lawyers which began on 9 July with the arrest of prominent human rights lawyer Wang Yu.

The petition, which has more than 2,000 supporters, called on the Chinese government to respect the rights of the detained lawyers, inform the families of their whereabouts, immediately permit access to their legal representatives and to stop unlawful conduct against lawyers.

It also called for any charges to be heard by a judicial process that is open, fair and transparent.

The 13 warned that only when lawyers’ rights are respected can the rule of law take root in mainland China.

‘It would be unfortunate and regrettable if the conduct of lawyers who fearlessly represent the causes of their clients (who may be at odds with the state) can be readily interpreted or characterised as criminal in nature,’ they said.

Of the 200 human rights activists and lawyers arrested in the crackdown, 13 still remain in police custody incommunicado, according to the rights group Human Rights Watch. At least six people, including a lawyer and a legal assistant, remain missing.

The group said lawyers and activists were originally targeted for supporting Beijing's Fengrui Law Firm.

Chinese state media reported that Zhou Shifeng, the director of Fengrui, has confessed, saying the firm had ‘broken the law’ and ‘brought great risks to social stability’.

The Law Society and Bar Council have both written to the Chinese premier Li Keqiang, urging the release of all those detained for defending the human rights of their clients.