The document called "Defense of Japan, 2011" -- approved by the Cabinet -- describes China's rapid modernization of its military hardware as an attempt to "strengthen its capacity to have its military potential reflected in distant locations."
Beijing's buildup of its maritime power and its defense policy in general, which was noted in last year's white paper, continues to be "a concern for the regional and the international community," a report by Yomiuri Shimbun newspaper said. China should "be aware of its responsibility as a major power and abide by international rules."
To mark Japan's concern over China, the Ministry of Defense created in the white paper a new section dealing with Beijing's activities specifically in the South China Sea, the Yomiuri Shimbun report said.
The document -- the longest annual defense report at nearly 600 pages -- says Japan fears the territorial disputes between China and its neighbors, in particular the dispute over the Spratly Islands, "will affect peace and security in regional and global society."
The Spratly Islands -- the largest group -- lie off the southwest coast of the Philippines as well as Brunei and Malaysia. Ownership of the Spratly Islands is the most difficult of all the territorial claims because of the number of claimants, including Vietnam and Taiwan.
Further north, off the west coast of the Philippines, lies the Scarborough Shoal, disputed between China and the Philippines. Meanwhile, Vietnam and China are fighting for sovereignty over the Paracels, a group of islands south of China's Hainan Island province and off the east coast of Vietnam.
The white paper concludes that China "can be expected to expand its sphere of naval activities and carry out operations as a routine practice in the East China Sea, the Pacific Ocean and the South China Sea."
There was praise for joint drills by Japan and the United States because they prepared both organizations to cope with disaster relief work in the aftermath of the devastating March Tohoku earthquake and tsunami. The operation was "particularly important to secure the life and safety of affected people."
At the time, Japanese Prime Minister Naoto Kan said, "In the 65 years after the end of World War II, this is the toughest and the most difficult crisis for Japan."
Police confirmed upward of 16,000 deaths, 5,700 injured and more than 5,000 people missing. Also, more than 125,000 buildings were damaged or destroyed.
The white paper praised Operation Tomodachi, meaning Operation Friends, a U.S. military assistance operation to support Japan in disaster relief following the earthquake. It included 20 U.S. naval ships, 140 aircraft and more than 19,000 sailors. The cost was around $80 million.
Japan's annual defense white paper comes after China signed an agreement last month with the Association of South East Asian Nations concerning peaceful resolutions of maritime disputes in the South China Sea.
The document was signed only several days after China complained to the Philippines over a Filipino politician's visit to a disputed Spratly island.
However, the China-ASEAN agreement, signed at the 44th ASEAN Foreign Ministers meeting in Indonesia, was welcomed by Chinese Assistant Foreign Minister Liu Zhenmin.
"This is an important milestone document on the cooperation among China and ASEAN countries," Liu told reporters at the meeting. "And we have a bright future and we are looking forward to future cooperation."
But there is concern among China's neighbors that Beijing is beefing up its maritime military hardware.
Beijing acknowledged last month it has in production its first domestically built aircraft carrier. It will complement the Varyag aircraft carrier, which it bought from Ukraine and is expected to begin sea trials this year.