Communist power is a "fundamental requirement" to ensure the rule of law in China, a party official said Thursday, days after a meeting of the organisation's top leaders in Beijing.

The ruling party's Central Committee announced a series of moves to centralise power and combat corruption following its Fourth Plenum meeting in the capital, saying it was pursuing the "rule of law with Chinese characteristics".

"The leadership of the Communist Party of China is a fundamental requirement for building the rule of law," Guo Yezhou, a deputy head of the Central Committee's international department, told reporters at a briefing.

"In order to keep the leadership of the Communist Party of China, we must depend on the development of rule of law in the country," he continued.

The Communist Party tightly controls China's parliament, military, police, prosecution and court systems, and anger at widespread injustice has emerged as an increasing problem for it.

The 16,000-character statement issued after last week's plenum stressed that Communist leadership "must be adhered to", listing the party above equality before the law and upholding the rule of law.

- Beyond judicial oversight -

The organisation's internal justice system, known as "shuanggui", operates without oversight from judicial authorities and has been increasingly criticised by China's legal community.

More than 15 officials have reportedly died from abuses in "shuanggui" since 2007.

Nonetheless, Guo declined to indicate whether it would be reformed, saying only: "'Shuanggui' is an inner party rule of the Communist Party of China."

Henry Gao, an expert on Chinese law at Singapore Management University, told AFP that compared with his predecessors, party chief Xi Jinping is less "hesitant" about emphasising the organisation's supremacy.

"You could argue that rule of law is inconsistent with the leadership of the party, because if you really want the law to be supreme, then nobody should be above the law, including the party," he said.

"But the decision made it really explicit that the party is going to be in charge," he added.

"Xi somehow now has this confidence in the leadership of the party -- in the ability of the party -- that he's out telling the world, 'You may not like it, but the party is in charge.'"

Authorities had been expected to reveal a decision on the fate of Zhou Yongkang, the powerful former security chief ensnared in Xi's anti-corruption drive.

But there has been no declaration yet about Zhou, whose investigation was announced in July, and officials said Thursday only that the details will be released "in due time".

"Zhou Yongkang no longer serves as a central leadership official; therefore, there is no decision related to this case in the Fourth Plenum," said Jiang Wei, head of the Office of Central Leading Group for Judicial Reform.

He added that the handling of Zhou's case "demonstrates the determination of our party to fight against corruption".