Beijing - China's oceanic environment was basically healthy in 2010, with 94 percent of the country's territorial waters being of the highest quality according to national standards, a government report has said.

Also, the majority of the marine offshore eco-systems were healthy or sub-healthy, said the report on China's oceanic environment for 2010, which was issued by the State Oceanic Administration (SOA) Friday.

Moreover, the number of algal blooms dropped slightly and offshore drilling had not disturbed nearby marine life or activities, it said.

However, the report said that water quality of 48,000 square kilometers of sea waters was below Level IV - the lowest level - and some marine ecosystems were in an unhealthy state.

Despite improvement in the quality of waste water discharged into the sea, 54 percent of the total cases involving waste water discharge failed to meet the national limit, it said.

The report said oil spills posed a serious environmental threat.

In order to strengthen preventive measures to control the risk of oil spills, all maritime drilling platforms had been required to update their emergency plans, said Li Xiaoming, a SOA official in charge of marine environment protection.

Li said the SOA was introducing a series of measures to monitor for radioactive materials discharged into the Pacific Ocean from the crippled Fukushima power plant in Japan, including 24-hour monitoring of sea waters most likely to be affected.

Due to the uncertain effects of the nuclear disaster, environment monitoring in the west Pacific would be a priority over the next five years, he added.