Rescue workers on Tuesday found seven more bodies in the Baixing mine in Heilongjiang province, raising the number of confirmed dead.

Five miners still missing had little chance of survival due to a build-up of poisonous gas, state media said.

Thousand of miners are killed in China every year despite repeated government promises to promote safety.

"The trapped had little chance of survival as a high concentration of poisonous gas in the air and fallen rocks make the rescue operations underground extremely difficult," Xinhua news agency said.

The government has made repeated efforts to improve safety standards at mines.

On Friday, it was announced that a Communist party official had been executed for covering up a tin mine accident which killed 81 people in 2001.

Wan Ruizhong, a former county party chief in Guangxi province, was found guilty of taking bribes from mine bosses to conceal the accident.

Official figures show that accidents in mines caused 7,197 deaths in the first 10 months of last year.