Ninety-six miners were feared dead after a coal mine gas blast in northern China yesterday, a grim toll likely caused by illegal mining and possibly made worse by delays reporting the accident, the Xinhua news agency said.

Rescuers had found 70 bodies in the village-run mine by early evening and were searching for at least 26 more, Xinhua quoted the rescue operation headquarters saying. Fifteen had survived.

But figures from the State Administration of Coal Mine Safety suggested the death toll from the Xinyao pit, in the major coal producing province of Shanxi, might rise higher, with 40 confirmed dead, 74 unaccounted for and 13 survivors.

The rescue team believes managers at the Xinyao mine delayed reporting the accident and instead tried to launch their own rescue operation, which increased the death toll, Xinhua said.

And although the mine was licensed, initial investigations showed that the explosion was caused by mining along a coal seam that had not been authorised for production.

Police have arrested the mine's head and legal representative, suspended its licence and frozen its bank accounts, while top safety officials have rushed to the site from Beijing, Xinhua added.

China has been trying to tighten safety regulations but its coal industry is still the world's deadliest, claiming close to 5,000 lives last year.