But the official also warned that China will find it near impossible to avoid serious accidents even after a chemical spill in November galvanized national concern about the ecological damage that has accompanied China's industrial boom.

"Due to the geographic distribution of environmental threats and structural environmental risks, for some time to come high-risk conditions for sudden environmental incidents will continue," the official said.

The spill in the Songhua River in far northeast China came after a blast at a chemical plant near its banks poured 100 tonnes of cancer-causing benzene into the river. It led to the shutting of water taps in cities and towns in Heilongjiang province, as well as emergency measures in Russia, where the river flows.

Chinese environmental officials have said many other dangerous factories crowd the sides of China's major rivers.

SEPA received official reports of 45 other pollution accidents in the two and a half months after the Songhua spill, and nine were caused by factories illegally expelling pollutants, the official told the People's Daily.

"The dramatic rise in environmental incidents is far from random," the official said.

Factories "only concern themselves with their immediate interests", ignoring pollution hazards, the official said. He cited a smelter in southern China's Guangdong province that dumped poisonous chemicals into the Beijing River in mid-December.

SEPA has issued guidelines for when and how different kinds of environment accidents, the official said.

The latest warning from the pollution watchdog came after its former head, Xie Zhenhua, resigned in early December for failing to properly report and monitor the Songhua River spill.

The spill drew widespread criticism and law suits over the government's response, mostly aimed at officials in Jilin province where the chemical plant is located.

But SEPA officials said at the time they received no reports from Jilin province officials for three days after the blast.

The Chinese government has promised to improve China's environmental safeguards and spent billions of yuan on cleaning up the country's rivers.

But the state-controlled Workers Daily reported on Tuesday that 4.55 billion yuan ($564 million) spent over 14 years on cleaning up the Dianchi Lake in southwest China's Yunnan province has done little to improve water quality.