China's communists have called the scandal surrounding disgraced politician Bo Xilai a "profound lesson" for the ruling party, as delegates gathered in Beijing on the eve of a key leadership congress.

The party's handling of Bo's case underlines the leadership's resolve to uphold integrity and prosecute corruption no matter how high ranking the culprits, congress spokesman Cai Mingzhao told a news conference.

The struggle against corruption remains long term, complex and extremely difficult, Mr Cai said. The 18th national party congress, which opens today, will thoroughly address the issue.

Loading article content

Its disciplinary arm will also adopt new measures in education, prevention, supervision and punishment, he said.

"Problems involving Bo Xilai... and others are serious corruption cases among our party's high-ranking leading cadres, and have offered a profound lesson," Mr Cai said.

Bo had been one of China's highest profile politicians and a candidate for higher office when he fell from grace amid a scandal over his wife's involvement in the murder of British businessman Neil Heywood. Bo dropped from view, and in September was expelled from the party and sent for prosecution on charges including corruption and interference in his wife's case.

Mr Cai also cited Liu Zhijun, a former railways minister who was expelled from the party and faces corruption charges.

National party congresses are held once every five years and this year's meeting will usher in a once-in-a-decade transition to a new generation of top officials led by Vice-President Xi Jinping.

In addition to selecting members of leading party organisations, the 2270 delegates at the party congress will hear and deliberate over the work of the party over the past five years, a party discipline report and revisions to the party constitution.