China's seas will contribute 3.16 trillion yuan (433 billion U.S. dollars), or more than five percent of the country's gross domestic product (GDP), in 2010, according to a report on China's marine development.
The report, issued on Friday by the State Oceanic Administration (SOA), also predicted the country's offshore crude oil output would exceed 50 million tons.
"China's development of ocean crude oil will enter into a speedy period," it said, adding that at the time, the country's natural gas development would grow quickly with key technologies greatly helping exploration.
It said China's current offshore oil and gas exploration was "still in an infant stage", with 80 percent of oil and gas resources yet to be tapped.
The country's explored crude oil only accounted for 17.6 percent of the reserve at sea, and natural gas that was tapped out only made up 11.9 percent of the national sea reserve, it said.
The report, mainly drawing from past experience so as to offer "strategic suggestions" to decision makers, singled out marine industries, included fishing, transport, oil and gas, tourism and shipbuilding.
"The sector is still in a growth period between 2007 and 2010 and the development mode will gradually turn to be more efficient," it said.
The throughput of major sea ports will surpass 5.6 billion tons in 2010, with "a relatively complete port transportation system being established," it said.
Shipbuilding capabilities in 2010 will reach 21 million tons, according to the report. Around 2020, China would become a world power in the sector. Last year, China's seas contributed 2.49 trillion yuan.