A former Chinese Communist Party official who was once tipped for a top leadership post was sentenced to life in prison for bribery on Tuesday, the latest senior cadre to fall in President Xi Jinping's sweeping anti-corruption crusade.

Sun Zhengcai, a former Politburo member and party chief of the southwestern mega-city of Chongqing, was found guilty of taking over 170 million yuan ($26.7 million) in bribes, the First Intermediate People's Court of Tianjin said in a statement on its website.

 Sun, 54, had once been tipped for promotion to the Politburo's elite seven-member standing committee, which rules the country and is presided over by Xi.

As the youngest Politburo member, Sun was even seen in some quarters as a potential successor to Xi.

 The court said the defendant had been given a "lenient" sentence in light of his willingness to cooperate with the investigation.

 In addition to his prison term, Sun's "stolen property has already all been confiscated," the statement said.

 A photo posted on the court's website showed the former leader in the dock, head deeply bowed as two police officers look on.

Sun had been accused of taking advantage of his position to seek profits for others and illegally accepting money, according to previous court statements.

He and his alleged associates were charged with accepting the bribes in return for providing help to unspecified organisations and individuals with engineering contracts, business operations and other matters.

His actions had "gravely damaged the normal work order of national organisations and harmed the integrity of conduct by national employees," the statement said.

 He pleaded guilty to the charges during a one-day trial in April.

Sun was the first serving member of the 25-person Politburo to be placed under investigation since Bo Xilai, another former leader of Chongqing, who was jailed for life in 2013.

Xi has presided over a popular anti-graft drive since coming to power in 2012 that has punished more than one million officials. Critics have compared it to a political purge.

 The National People's Congress recently expanded the campaign by creating a national supervision commission that will look beyond party officials and scrutinise millions of public servants at all levels of government.

 In October, senior party official Liu Shiyu congratulated Xi for foiling the efforts of powerful officials who "plotted to usurp the party's leadership and seize state power."

Liu listed former security czar Zhou Yongkang alongside Sun and Bo as part of the conspiracy, which was rumoured to have involved military officials.

All three have been ousted from the ruling Communist party (CCP) and arrested or jailed on corruption charges.

As the country's fourth largest city and an industrial metropolis in the southwest of the country, Chongqing is a major post for ambitious politicians.

When Sun became Chongqing's chief in 2012, he was tasked with erasing Bo's influence on the city.

But last year the party's discipline inspectors publicly rebuked Sun for failing to get the job done. His downfall came months later.