One of China's most outspoken human rights lawyers has been charged with inciting ethnic hatred, a Beijing prosecutor said, the latest development in a case that has drawn censure from the West.

Pu Zhiqiang, 49, has also been indicted for "picking quarrels and provoking troubles," charges that a string of political dissidents, including lawyers, activists and journalists, have faced.

The second branch of the Beijing People's Procuratorate said via its official microblog that Pu had harmed social order. His online writings that touched on political and social issues, including treatment of minorities, had prompted the charges.

The United States has repeatedly called on China to release Pu. State Department spokesman Jeff Rathke repeated that message.

"His indictment appears to be part of a systematic pattern of arrests and detentions of public interest lawyers, Internet activists, journalists, religious leaders and others who challenge official Chinese policies and actions," Rathke said.

China said that the United States should look at its own human rights record rather than criticise others.

Pu was arrested last June on charges of causing a disturbance and illegally accessing personal information in a case that drew international condemnation.

Pu said in December he had denied all accusations against him, including inciting ethnic hatred and separatism, charges that could lead to life in prison.

Pu's supporters say the case against him is politically motivated.

"The charges against Pu Zhiqiang are another act of political persecution. The chances of him receiving a fair trial are close to zero," said William Nee, China Researcher at Amnesty International, in a statement after the indictment.

Pu has represented many well-known dissidents, including artist Ai Weiwei and activists of the "New Citizens' Movement," a group that has called on Chinese leaders to make their wealth public.

He also opposed forced labour camps, which the government has abolished, and he was featured prominently in state media for that campaign - unusual for a government critic.

Pu was first detained last May after he attended a meeting in a private home to commemorate the bloody suppression of pro-democracy protests in and around Tiananmen Square in 1989.