A Chinese court has jailed for life a former senior aide to retired president Hu Jintao after finding him guilty of taking bribes, illegally obtaining state secrets and abuse of power during a secret trial.

The ruling Communist Party announced its investigation into Ling Jihua in December 2014, in a case that the party has said caused major damage to its image.

He had been demoted in September 2012 from a ministerial-level job, months after his son was killed in a crash involving a luxury sports car.

The court in the northern city of Tianjin, close to Beijing, held the case behind closed doors on June 7, according to a statement reported by the official Xinhua news agency.

"Ling Jihua took an extremely large amount of bribes. He obtained a large number of state secrets, and the crimes were very serious. He abused his power, and caused a terrible impact upon society," Xinhua said.

Ling accepted the facts of the case and did not contest them, it added.

It has never been possible to reach Ling for comment, and unclear who his lawyer was or if he was appointed for Ling by the party.

Ling's case had presented a dilemma for the government, because of his close connection with former president Hu, President Xi Jinping's predecessor.

A government spokesman denied last year that Hu was being implicated in the investigation and sources have told Reuters Hu approved of the case against Ling.