A court in northeastern China has upheld a life sentence imposed on a former aide to disgraced Politburo member Bo Xilai, it was announced on Monday.

Wu Wenkang, a key assistant to imprisoned former senior official Bo, had been sentenced to life in prison for taking bribes of 20 million yuan ($3 million).

Wu, 57, a native of Liaoning province, was director-general of the administration office of the Communist Party Committee in Chongqing before he was held on corruption charges in October 2012.

On Monday, the full text of Wu's verdict was made public by the High People's Court in Jilin province, where he appealed, making the case the latest incident in the sweeping nationwide anti-corruption drive.

The document said Wu was sentenced to life imprisonment in November 2014 for using his public positions in Liaoning province and Chongqing to make money illegally from local land development, from granting projects to others and helping others to obtain bank loans from 1999 to 2012.

The Intermediate People's Court in Changchun, Jilin, found him guilty of the corruption charges and sentenced him to life in prison.

The High People's Court in Jilin, a higher level court, upheld the verdict in March last year.

It was not made public until Monday.

Wu's lawyer, Ding Fengli, applied to the appeal court for a lenient sentence.

Ding argued that Wu had turned himself in to the central government working group when it investigated an incident in which Wang Lijun, the police chief in Chongqing, sought asylum at the United States consulate in Chengdu and in which Bo, the top official in the city, was found to be involved in a series of crimes.

Wu's defense was rejected by the court, which found that the Central Commission for Discipline Inspection had filed a case against him before he confessed.

Bo was the top official in Liaoning province and later in Chongqing from 1999 to 2012.