BEIJING (Reuters) - China's ruling Communist Party needs rules that strengthen the "leadership core", the party's official newspaper said on Monday, hinting at further centralization of power for President Xi Jinping after decades of collective leadership.

The party has already announced that the Rules on Intra-Party Political Life will be discussed during its four-day plenum, which opened on Monday.

The rules were introduced in 1980 to prevent any cult of personality after Chairman Mao Zedong's rule plunged the country into anarchy during the 1966-1976 Cultural Revolution, when Mao declared class war.

The rules are designed to set in stone that power cannot not be put in the hands of just one person, or a small group of people like the Gang Of Four, led by Mao's widow, which tried to seize power after Mao's death in 1976.

In a lengthy front-page commentary, the official People's Daily said that since 1980, the rules had ensured the party's internal political life had "returned to normal" and helped usher in three decades of economic boom.

Now, 36 years on, the plenum of the party's top leaders will set new rules, the newspaper said.

This will "forge an even stronger, energetic leadership core, ready and waiting to guide China at its new starting point".

The paper did not say exactly how the rules would change.

Late paramount leader Deng Xiaoping coined the phrase "core" leader to refer to Mao as Communist China's first generation leader, himself as second generation and Jiang Zemin as third generation, meaning they have almost absolute authority and should not be questioned.

But Xi has yet to assume that mantle.

Since assuming office almost four years ago, Xi has rapidly consolidated power, including heading a group leading economic reform and appointing himself commander-in-chief of the military, though as head of the Central Military Commission he already controls the armed forces.

The paper said that whenever the party's internal political life was "abnormal", that was when crises and chaos erupt, pointing to the Cultural Revolution as well as the 1958 Great Leap Forward campaign when millions died of starvation from 1959 to 1961 in a disastrous attempt at rapid industrialization.

The plenum will be conducted in strict secrecy and once it ends on Thursday, the official Xinhua news agency will issue a wordy communique on what it has achieved, full of turgid communist phraseology.

Xinhua said early on Monday in a brief dispatch the plenum had begun.

New rules on pushing forward Xi's campaign against deep-rooted corruption would also be unveiled at the plenum's end, state media has said.  

(Reporting by Ben Blanchard and Benjamin Kang Lim; Editing by Nick Macfie)