China's parliament is set to water down controversial changes to a law that would allow secret detentions, people with knowledge of the issue said Monday, following an outcry over the move.

The National People's Congress, opening its annual session next Monday, will remove some planned changes to the Criminal Procedure Law that would have made it legal to lock up suspects in secret locations for six months without charge.

Chen Guangzhong, the influential honorary chairman of the China Legal Society, told AFP he had seen the latest draft of the law, and legislators had deleted some of what critics have dubbed the "disappearance clauses."

These clauses ruled that police did not have to tell family the whereabouts of suspects arrested, detained or under surveillance in national security, terrorism or major graft cases, if such notifications impeded a criminal probe.

The clauses triggered an uproar, with critics saying the changes amounted to legalising human rights violations. Prominent activist Hu Jia compared them to methods used by the former Soviet Union's KGB secret police.

The practice of so-called "enforced disappearances" already exists in China, but the amendments would have given it extra legal clout.

Rights lawyer Gao Zhisheng, for instance, was taken away in 2010 and was held largely incommunicado for nearly 20 months. Nobel Peace Prize winner Liu Xiaobo also suffered from these "disappearances."

But Chen told AFP the latest draft of the law -- to be voted on during the NPC's session -- now rules that police inform family members of the whereabouts of suspects arrested or placed under residential surveillance within 24 hours.

"This is a new breakthrough in the amendment and is an added safeguard for human rights. The draft should now have no problem in passing -- there is an over 90 percent chance it will pass," he told AFP.

But he cautioned that in the case of criminal detentions -- legally different to arrests -- police have been given a longer period of 37 days to inform families, if such a notification impedes their investigation.

Nicholas Bequelin, a researcher at Human Rights Watch, told AFP "numerous (China-based) diplomatic sources" also told him Chinese officials had informed them the clauses would be removed.

"But I am quite skeptical about this mainly because they have refused to publish the draft amendment. The fact they are not disclosing the draft is an indication that it is still not settled," he said.

Calls to the NPC's press office went unanswered.