China's top Communist Party members will meet on Saturday, 12 months before a generational change in leadership, to discuss media controls in the face of a growing challenge from the Internet.

Around 500 senior party leaders will attend a secretive four-day plenum at a hotel in Beijing, their penultimate annual meeting before October 2012 when President Hu Jintao will end his second five-year term as party head.

Hu will preside over just one more plenum in October 2012 before his resignation, which begins a 10-yearly process that will culminate in the end of his presidency at a parliamentary meeting in March 2013.

Premier Wen Jiabao and his government will also resign in 2013 and analysts said this weekend's meeting would provide a final opportunity for the exiting regime to leave its mark on the direction of the party.

A brief statement said the main focus of the four-day plenum would be "cultural reforms" -- code, say analysts, for ensuring China's media and Internet companies serve the party's goals.

China now has more than half a billion Internet users, posing a huge challenge to government efforts to control public opinion as people go online to share information unavailable in state-controlled newspapers and television.

A train crash that killed 40 people in July sparked an outpouring of online fury that appeared to catch China's leadership by surprise.

Since then, there has been a concerted attempt to muzzle the hugely popular weibos -- microblogs similar to Twitter that have taken China by storm since they first launched two years ago.

At the same time, say analysts, some traditional media have become increasingly commercial as they seek to attract larger audiences and compete with the web.

"The reform of the cultural system has to do with ensuring that the media, publications, movies, Internet, et cetera serve the partys goal of galvanising patriotic and nationalistic sentiments," said Willy Lam, expert in Chinese politics at the Chinese University of Hong Kong.

"This will mean even tighter control over peoples freedom of expression, especially on the Internet."

Cheng Li, an expert on Chinese politics at the Brookings Institution in Washington, said the reforms would address the challenge of an increasingly powerful media.

"The Chinese leadership recognises the growing political and cultural pluralism in the Chinese society, the trend of commercialisation of media, and the increasing power of social media," he told AFP.

"These are daunting challenges for the CCP (Communist Party) regime. The plenum aims to reach some sorts of consensus and policy guideline in the leadership on this front."

China's Communist Party is the largest political party in the world with more than 80 million members.

"The outgoing leadership will sing what may be perceived as their swansong to the ambitious successors, patiently waiting in the wings," said Jean-Pierre Cabestan, a China scholar at Hong Kong Baptist University.

Little is known for certain about the political transition, but Vice President Xi Jinping is widely expected to take over Hu's posts as head of the party and head of state, while Vice Premier Li Keqiang is tagged to be the next prime minister.

The top Communist Party posts, collectively known as the Politburo Standing Committee which currently numbers nine, will be settled about three months before next October's party congress, but not made public until it concludes, analysts say.

"There will be discussion over personnel issues over the four-day plenum, but these will be totally behind closed doors," said Lam.

"There will be jockeying for position, but nothing definitive on personnel issues will be settled."

The plenum comes amid wholesale changes in the massive government bureaucracy of the world's second largest economy as part of the transition, as future generations of leaders move up the ranks.

But analysts said the talks would focus on the proposed cultural reforms, which Cabestan described as an attempt by the party to "remind everyone who and what ideology is in the driving seat".