US oil giant ConocoPhillips, already facing growing public condemnation and law suits for its previous oil spills off China's northern coast, has found seven new leaks, maritime authorities said on Friday.

According to the State Oceanic Administration (SOA)'s North China Sea branch, ConocoPhillips on Thursday admitted the discovery of the new leaks near the Platform C of the 19-3 Oilfield in the Bohai Bay.

The company only last week reported nine leaks near the same platform.

The US company is facing legal action and mounting public anger after thousands of barrels of oil and oil-based mud have leaked from its platforms in the Bohai Bay since June, polluting beaches and killing marine life in the area.

Liu Cigui, head of the SOA, said Thursday that his administration is collecting evidence and gauging the ecological impact of the spills in preparation for possible legal action against the company.

"Any company that damages China's oceanic environment must pay for their actions," Liu said during a teleconference on the handling of the incident, during which he referred to the spills as the "worst oceanic environmental accident" in Chinese history.

ConocoPhillips China, a subsidiary of ConocoPhillips, first reported the oil spills in June. The spills have spread to beaches in Hebei and Liaoning provinces and been blamed for losses in local tourism and aquatic farming industries.

Wang Fei, an SOA official, said on Thursday that a total of 5,500 square km of the bay's surface has been contaminated, with 870 square km seriously polluted, meaning that it is unfit for swimming and aquatic farming.