For years, the leadership has been loath to admit the existence of a legitimacy crisis.

But the issue has received increasing attention as the party completes its transformation from revolutionary group to ruling political party, playing down ideology to the extent of opening its door to entrepreneurs.

The party leadership has given ample clues as to what the plenum, which runs from next Thursday to Sunday, will discuss. A group study session of the Politburo on June 29 focused on building effective party leadership. The theme was repeated in a speech by President Hu Jintao at the centenary of Deng Xiaoping's birth on August 22.

'Democratic centralism' and internal discipline will be at the core of the moves to strengthen leadership but political reforms will not be addressed, analysts say.

The plenum will, however, provide examples of widening democratic channels within the party, such as experiments with checks and balances and the filling of local posts through multi-candidate elections. Promulgating regulations on internal supervision will also be cited as evidence of the party's resolve to strengthen itself.

In the run-up to the plenum, signs of factional struggles at the top have fuelled speculation that former president Jiang Zemin , who retains the powerful position of chairman of the Central Military Commission, will step down following the example of Deng, who relinquished his military post at the fifth plenum of the 13th party congress in November 1989.

Mr Hu recently praised Deng's move to stop cadres serving for life and the fact that he served as a personal example.

There has been friction over the macro-economic policies used to cool down the economy, with Mr Hu and Premier Wen Jiabao pursuing a tightening of credit that has hurt business interests associated with Mr Jiang's camp. Media reports say Shanghai party secretary Chen Liangyu has also had harsh words to say about the measures. But analysts said that the pressure on Mr Jiang to step down was not yet strong enough and he was likely to serve out his five-year term until the 17th party congress in 2007.

The emphasis on party self-strengthening in the plenum essentially papers over differences between Mr Hu and Mr Jiang.

Building effective party leadership, in fact, has been a recurring call since the early days of the reform and opening 25 years ago. The party also learned a few salient lessons from the collapse of communist regimes in eastern Europe and Russia in the early 1990s. Strengthening the party's ability for governance was formally written into the charter at the 16th party congress in November 2002.

Some sources said a proposal to uphold 'rule of law' within the party had died in wrangling among the highest echelons, so any self-policing system would be diluted. 'The leadership likes to talk about the party cleansing itself, but there is no consensus on how to implement it,' one analyst said.

Yu Yunyao , vice-chancellor of the Central Party School, noted that, as in other developing market economies, China would find itself at a critical period of development when per-capita gross domestic product grew from US$1,000 to US$3,000. The period of social unrest, as a result of rising expectations, would pose a test of the ruling party's ability to maintain stability. It was a pressing task to strengthen the party, he said.

The plenum will bring together about 300 members and alternate members of the Central Committee of the Communist Party and its discipline committee to listen to the work report of the committee's Politburo and pass a resolution as the guideline for actions.