An accident at a coal mine in southwest China killed 21 miners Tuesday, state media said, in the latest disaster to hit the country's troubled industry.

Four others were missing after the coal and gas outburst at the Machang coal mine in Guizhou Province, Xinhua reported citing local authorities, adding that 58 more had managed to get to the surface safely.

China's mines are among the deadliest in the world due to lax regulation, corruption and inefficiency. Accidents are common because safety is often neglected by bosses seeking quick profits.

Official figures show 1,973 people died in coal mining accidents in China in 2011, a 19 percent fall on the previous year.

Labour rights groups, however, 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.

China is the world's biggest consumer of coal, relying on the fossil fuel for 70 percent of its growing energy needs.