Thirteen miners were still trapped underground at the remote Sizhuang Coal Mine in Shizong county, in the south-western province of Yunnan, according to Xinhua.

"The air is thin and the chances of survival for the trapped miners are slim," the provincial rescue headquarters earlier said in a statement.

Families of the victims will get a compensation package of 660,000 yuan ($73,500), while 17 of them have already received 10,000 yuan for funeral expenses.

Hundreds of rescuers are continuing the search, in which about 240 tonnes of coal dust have been removed and a 250-metre stretch of tunnel cleared.

The mine was hit Thursday by a "coal and gas outburst" - a sudden and violent ejection of coal, gas and rock from a coal face.

Xinhua said the mine was operating without a licence after its permit was revoked a year ago.

The chief of China's work safety watchdog, Luo Lin, described the mine's safety measures as "very poor" and blamed lax supervision by local authorities.

The mine's bosses have been detained and an investigation is under way.

"The latest coal mine accidents ring the alarm, warning us that accident prevention is a complex, difficult, and urgent task," China's vice premier Zhang Dejiang was quoted as saying.

Coal mine accidents are common in China, where work safety is often neglected by bosses seeking a quick profit.

Last year, 2,433 people died in coal mining accidents in the country, according to official statistics - a rate of more than six workers per day.

But labour rights groups say the actual death toll is likely to be much higher, partly due to under-reporting of accidents as mine bosses seek to limit their economic losses and avoid punishment.

-AFP