China will make an all-out effort to protect its marine environment, which is facing very serious pollution threats, said the country's top environment official Monday.

"China is a country with huge marine resources, and its oceans and coastal regions are crucial parts of the country's economy," said Zhou Shengxian, director of the State Environmental Protection Administration (SEPA).

"But pollution control in and along China's rivers and seas is still under great pressure," Zhou said, adding that pollution originating on land had been on the rise for many years.

Zhou made the remarks in Beijing at a five-day GPA workshop, a global UNEP (the United Nations Environment Programme) program on action to protect the marine environment.

"Marine environment crises occur regularly in China, and pollution is still very serious at the mouths of major rivers and some bays," Zhou said.

Measures to clean up the environment will focus on northeastern Bohai Bay, the areas around the mouth of the Yangtze River and the southern section of the Pearl River in Guangdong Province, he said, adding that sewage discharge would be restricted in these areas.

The three key areas pinpointed by Zhou are close to China's three major economic engines -- the Bohai industrial belt, the Shanghai region, and the Pearl River Delta in Guangdong, bordering Hong Kong.

Zhou took over the SEPA office last December after his predecessor Xie Zhenhua was sacked over a chemical spill that seriously polluted the country's northeastern Songhua River.

Cities along the river, including Harbin, capital of Heilongjiang Province and a city of more than 3 million people, were forced to temporarily shut down tap water. Russian environmental officials were then mobilized to join pollution control efforts as pollutants flowed down the river towards China's northern neighbor.