President Xi Jinping has vowed to step up a crackdown on corruption in key sectors, including finance, energy and infrastructure, state media reported.

Xinhua news agency quoted Xi as saying on Monday that the nation's fight against corruption has achieved an "overwhelming victory", but the situation remains grave and complex.

In the speech to the Communist Party's anti-graft agency, Xi ordered "greater efforts" to fight corruption in "finance, state-owned enterprises, energy, medicine and infrastructure", Xinhua reported.

"We should be fully aware of new developments in the fight against corruption and the breeding grounds and conditions for corruption," he said.

Broadcaster CCTV reported on Monday that a former top executive at a state-owned oil and gas giant had been arrested for suspected bribery.

And the same day, the anti-graft agency announced an investigation into the former head of the economic operations office of the state-owned tobacco monopoly.

Late last month, a former vice-chairman of the country's banking regulator was sentenced to life imprisonment, state media reported. (AFP/Reuters)