Xinhua reported that Mr Huang died in Beijing at 2.30am. Sources said Huang, a Zhejiang native, had been at the People's Liberation Army 301 Hospital in Beijing. The government followed its usual practice of not giving any specific details about his illness, but it was reported in February last year that Huang had been diagnosed with pancreatic cancer.

When Hong Kong-based Phoenix Television and The Times of London reported on May 9 that Huang had died, the reports were denied that day by the central government.

The news of his death yesterday at the age of 68 was announced five days after Huang was appointed a Shanghai delegate to attend the 17th party congress, to be held in Beijing in October.

Although Huang never formally retreated from the political stage, analysts believed his political influence dwindled after he fell ill and that his death will not affect the leadership lineup to be announced at the 17th party congress.

Liu Junning , a Beijing-based political analyst, said: 'I don't think that [his death] will have much impact on the party congress. He was a top leader, but he not a core member in the leadership. His work in the cabinet has already been taken up by Vice-Premier Wu Yi .'

Yuan Weishi, a Guangdong-based historian, said although the party could appoint a replacement for Huang on the Politburo Standing Committee, this was unlikely to happen so soon before the congress. Professor Yuan also believes Huang is one of only a few members of the party's top echelon to die of natural causes in office.

An obituary issued by the central authorities praised Huang as 'an excellent member of the [party], a long-tested and faithful communist fighter and an outstanding leader of the party and the state'.

Reports had alleged Huang's wife, Yu Huiwen, was implicated in financial scandals following the toppling of Shanghai party boss Chen Liangyu, but Huang made several high-profile appearances to indicate he was still in power.

His last public appearance was at the National People's Congress in March, when he made a surprise visit to the Shanghai delegation and urged them to back the anti-corruption drive by President Hu Jintao which toppled Chen.

With Huang's death coming at a sensitive time, only two days ahead of the June 4 anniversary, mainland media have been ordered to use only Xinhua's dispatch to report his death. Only positive messages such as those offering condolences were allowed in online chat rooms, industry sources said. Negative comments or political speculation about Huang's life were all banned.

Huang, a close ally of former president Jiang Zemin , was promoted to the Politburo Standing Committee in 2002 when Mr Jiang loaded the top echelon with allies to counterbalance the power of Mr Hu.