Police in the southern Chinese island province of Hainan will board and search ships that trespass into what China deems its territorial waters in the South China Sea, state media said Thursday.

The South China Sea is Asia's biggest potential military trouble spot with several Asian countries claiming sovereignty.

New rules, which come into effect Jan. 1, will allow Hainan police to board and seize control of foreign ships that "illegally enter" Chinese waters and order them to change course or stop sailing, the official China Daily reported.

"Activities such as entering the island province's waters without permission, damaging coastal defense facilities and engaging in publicity that threatens national security are illegal," the English-language newspaper said.

"If foreign ships or crew members violate regulations, Hainan police have the right to take over the ships or their communication systems, under the revised regulations," it added.

The China Daily said the “regulation revisions” were passed by the Hainan People's Congress on Tuesday.

Calling the revisions "significant", Zhuang Guotu, director of the Southeast Asian Center at Xiamen University, told the paper: "It is urgent for China to improve its legal system regarding offshore law enforcement because disputes with other countries are on the rise in the South China Sea. Police have clear processes laid out in the new regulations for appraising illegal activities and punishing illegal entry."  

The China Daily reported that an “insider from China Marine Surveillance” said new ships will join the South China Sea patrol fleet soon.

On Nov. 12, a 3,000-metric-ton inspection ship started patrolling the Yellow Sea, and on Nov. 15, another joined the patrol fleet in the East China Sea.

All these moves show that the country is preparing itself for dealing with complicated marine disputes, said Qi Jianguo, a former Chinese ambassador to Vietnam.

China's assertion of sovereignty over the stretch of water off its south coast and to the east of mainland Southeast Asia has set it directly against Vietnam and the Philippines, while Brunei, Taiwan and Malaysia also lay claim to parts, Reuters notes.

China occasionally detains fishermen, mostly from Vietnam, who it accuses of operating illegally in Chinese waters, though generally frees them quite quickly.

Hainan, which likes to style itself as China's answer to Hawaii or Bali with its resorts and beaches, is the province responsible for administering the country's extensive claims to the myriad islets and atolls in the South China Sea.

The stakes have risen in the area as the U.S. military shifts its attention and resources back to Asia, emboldening its long-time ally the Philippines and former foe Vietnam to take a tougher stance against Beijing.

China has further angered the Philippines and Vietnam by issuing new passports showing a map depicting China's claims to the disputed waters.