China's ruling Communist Party said Wednesday its highly anticipated congress would last for one week, as it signalled Vice President Xi Jinping had moved closer to taking the reins of power.

Xi was tapped for a key post overseeing the five-yearly congress that opens Thursday in Beijing. At the meeting, he is expected to replace President Hu Jintao as party chief in a once-a-decade power transition.

"The preparatory meeting passed the appointment of Comrade Xi Jinping as secretary general of the congress," said Cai Mingzhao, official spokesman for the party congress.

The move likely signals that Xi's much-expected ascent to the country's top leadership post is on track.

Xi, 59, has been number two to Hu since 2008. His likely appointment to head the all-powerful party at the congress's close will set the stage for his promotion to president of the world's most populous nation, expected next March.

Xi and the rest of the future leadership take the reins amid growing pressure for the party to reform to curb rising corruption and spur economic growth, which recently slowed to its lowest quarterly rate since 2009.

"(The congress) will be one of great importance, when China is in a crucial stage of building a modern and prosperous society in all respects, taking on reform and opening up, and accelerating the transformation of the growth pattern," Cai said at a press briefing.

He added that the congress would close on November 14 and confirmed that a new set of leaders to the party's Politburo Standing Committee -- China's top decision-making body -- would be unveiled at the end of the congress as per tradition every 10 years.

The party had not previously said how long the sensitive meeting would last.

Eight out of 10 Chinese want political reform and two-thirds feel the government should face greater public scrutiny, according to a survey of residents of major cities published on Wednesday in the state-run Global Times newspaper.

Elements in the ruling party are widely believed to favour some form of political reform to bolster its legitimacy, but the exact nature of any internal debate remains unknown due to the secrecy surrounding its affairs.

The lead-up to the congress has been tense due to the months-long controversy over former senior leader Bo Xilai.

Bo, the former party boss in the southwestern mega-city of Chongqing, was once seen as a candidate for promotion to the party's top echelons.

But he was brought down earlier this year by murder allegations against his wife and faces trial for abuse of power and other charges in a case that political observers say has revealed divisions among the senior leadership.

Of the Bo case, Cai said "the lessons have been extremely profound."

He offered no details on the political impact within the party but said Bo's downfall reflected "the strong resolve and unequivocal attitude of the party to uphold integrity and fight corruption."

Preparations for the closed-door power handover come as Americans re-elected President Barack Obama in the full glare of the world's media, prompting pungent comment by Chinese Internet users at their own lack of democracy.

"Why has the Chinese people's interest in the US presidential election reached a new high? Because the Chinese people have given up their own affairs... they are not allowed to handle them!" said a posting on a microblog service run by Internet giant Tencent.

Authorities in Beijing have tightened up security ahead of the congress and deployed a huge security presence, especially around the Great Hall of the People, the Stalinist edifice next to Tiananmen Square where it will be held.

Hundreds of activists have been put under house arrest, rights groups have said, while taxi drivers have been told to lock their back windows apparently to prevent passengers from throwing out flyers with political messages.