At least 25 miners have died after a fire broke out at an illegal coal mine in central China, state media has said.

The fire at a mine near Zhengzhou, capital of Henan province, is thought to have been caused by an electrical fault, the official Xinhua news agency said.

The mine's owner, manager and an investor were detained by police late on Monday following the blaze, Xinhua said.

The incident is the latest in a series of to hit China's disaster-prone mining industry.

Six miners in the pit at the time of the fire managed to escape, but others working in mine were burned to death, police said.

China's coal mines are the world's deadliest, claiming the lives of thousands of miners every year.

Labour rights groups say safety standards often ignored in the quest for profits and the drive to meet surging demand for coal, which provides about 70 per cent of China's energy.

The government has vowed to step up enforcement of workplace safety laws and crackdown on illegal and unsafe mines.

But a high demand for coal and a ready supply of cheap and willing labour means that for many mine operators the temptations of a fast profit are too great.

Earlier this month, more than 30 miners were killed in a flood at a coal mine in the Inner Mongolia region in northern China.