China intends to double its offshore air patrols by 2015, according to a government report released on Wednesday.

China's Ocean Development Report (2013), which was released by the China Institute for Marine Affairs under the State Oceanic Administration, emphasizes the importance of offshore air patrols to the country's maritime law enforcement.

According to the report, by 2015 the country's marine surveillance force will include fixed-wing aircraft with a range of more than 4,500 kilometers.

By 2020, a variety of aircraft with different ranges will be available for different purposes, according to the report.

China has undertaken regular patrols of the waters in the East China Sea since July 2006, and conducted regular patrols over the waters of the South China Sea since December 2007.

A senior China Marine Surveillance official, who wished to remain anonymous, said more aircraft will increase the frequency of offshore air patrols. Fixed-wing aircraft have higher maximum takeoff weights, which means they will be able to carry more equipment.

Offshore air patrols are being beefed up because the most direct maritime security problems are security threats posed by sovereignty disputes over islands.

To better meet these threats, the country also plans to unify its four maritime law enforcement agencies into a Maritime Police Bureau under a restructured State Oceanic Administration.

The agencies are the China Marine Surveillance under the State Oceanic Administration, the fishery administration under the Ministry of Agriculture, the coast guard forces under the Ministry of Public Security, and the maritime anti-smuggling authorities under the General Administration of Customs. The latest information on the restructuring will be released in a timely manner on the Oceanic Administration's website.

China Marine Surveillance, the maritime law enforcement agency under the State Oceanic Administration, has 10 aircraft, six fixed-wing aircraft and four helicopters at present.

Wang Fang, a researcher on marine policy and management with the China Institute of Marine Affairs, said the restructuring will definitely strengthen the country's offshore law enforcement capabilities.

During the past year, Sino-Japanese relations have become increasingly strained because of Japan's repeated provocations over the Diaoyu Islands in the East China Sea. The waters in the South China Sea remains troubled since a Philippine warship entered China's territorial waters around Huangyan Island and harassed Chinese fishermen in April last year.

Gao Hong, a professor of the Institute of Japanese Studies at the Chinese Academy of Social Sciences, said the ongoing territorial row between China and Japan over the Diaoyu Islands will not be solved in the short term, and the maritime economy is increasingly important to China.

Besides offshore air patrols, the report estimates that the gross domestic product involving the country's marine sectors will increase by 15 percent annually until 2030.

The GDP involving the marine sectors in 2012 increased 7.9 percent year-on-year to more than 5 trillion yuan ($814 billion), accounting for 9.6 percent of the country's GDP.