China has ordered lawyers to pledge allegiance to the ruling Communist Party in a new edict that has caused outrage among rights attorneys, who say it goes against the rule of law.

Lawyers applying for new or renewed licences will now be required to swear an oath of allegiance to the party and to socialism, according to a statement posted on the justice ministry website.

In recent years, Chinese authorities have struggled to maintain social order due to widespread anger over graft, government and police abuse and a yawning wealth gap, sometimes resorting to extra-legal means to crack down on dissent.

Civil rights lawyers have often been targeted by these clampdowns as authorities try to stop them from defending government critics or dissidents, or publicising their cases.

"I pledge to faithfully fulfil the sacred mission (and) be loyal to the homeland, loyal to the people, support the leadership of the Communist Party of China and uphold the socialist system," part of the oath reads.

Rights lawyer Liu Xiaoyuan said he opposed the oath, which marks the first time lawyers will be required to pledge support to the ruling party.

"Lawyers are not like judges and prosecutors, they don't have any public power and should only be loyal to the constitution and laws, and abide by professional ethics and discipline," Liu told AFP.

Lawyers should only pledge to safeguard the legitimate rights and interests of their clients and defend the dignity of the law, he said.

Other Chinese rights lawyers, many of whom remain under police surveillance or face routine harassment, refused to comment about the move out of concern for their safety.

"Ordering a lawyer to take such an oath is like an attack on rule by law," one prominent lawyer -- who asked not to be named -- told AFP.

"The state says it wants to establish a legal system in accordance with the constitution, so lawyers should pledge allegiance to the constitution. It is not right to pledge allegiance to a political party or organisation."