China has formally detained a dozen people over huge explosions in the city of Tianjin this month that killed at least 139 people, and has accused 11 officials and port executives of suspected dereliction of duty or abuse of power.

Anger over safety standards is growing in China, after three decades of swift economic growth marred by incidents from mining disasters to factory fires, and President Xi Jinping has vowed that authorities will learn the lessons paid for with blood.

News of the detentions comes a day after the ruling Communist Party sacked the head of China's work safety regulator, a former vice mayor of Tianjin, for suspected corruption, but without making an explicit link to the deadly chemical blasts.

The chairman, vice-chairman and three deputy general managers of Tianjin Ruihai International Logistics Co Ltd, owner of the warehouse that blew up, were among those who were "criminally detained", the state-run Xinhua news agency said on Thursday.

In an English-language report, the agency said they had been arrested. In China, criminal detention precedes arrest, which happens only once police level formal charges.

Separately, the state prosecutor said on its website a probe into the incident had found officials from a range of agencies to have been irresponsible, negligent and lax in the supervision of Tianjin Ruihai.

Among these agencies were Tianjin's transport, land resources, work safety and customs offices, besides state-owned port companies.

It named 10 officials suspected of dereliction of duty and one suspected of abuse of power.

There were 139 people confirmed dead in the blasts that flattened part of the port, while 34 remain missing.