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

Xi, who began his second decade as China's top leader in 2022 in a break with longstanding political norms, has waged a fierce campaign against corruption since taking power.

Proponents say the campaign promotes clean governance, though critics counter that it serves as a vehicle for Xi to purge political opponents.

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

"An overwhelming victory has been achieved in the fight against corruption, with the gains fully consolidated" over the last ten years, Xi said, according to Xinhua.

But "the situation remains grave and complex", he warned.

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

Around 4.8 million party officials in China have been investigated since 2012, according to the latest official figures from June 2022.

Of those, over 1.5 million have been handed punishments ranging from lengthy prison sentences to dismissal from official posts, demotion and expulsion from the party.

In recent months, the campaign has swept through industries including banking, insurance, state-backed business and sport.

State broadcaster CCTV reported 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.