This year’s defense white paper underscores China’s rapid military buildup and constant muscle-flexing in the Pacific Ocean as a shared concern of the international community.

“The situation surrounding East Asia has been rapidly changing,” Satoshi Morimoto, the fourth defense minister to take office since last year’s report, said Tuesday after the white paper was approved by the Cabinet.

Morimoto said Japan needs to keep in mind the significant changes in China and North Korea over the past year.

In North Korea, a power transfer occurred in December with the death of longtime leader Kim Jong Il. His son, Kim Jong Un, was appointed the new leader.

In April, North Korea tried to launch a rocket in what many experts saw as a cover to test a long-range missile. The rocket fell into the sea soon after liftoff.

The white paper says China is continuing to boost its military spending, which has expanded about 30-fold over the last 24 years. Defense topped the $100 billion mark for the first time in the 2012 budget, but the paper also notes that such figures provided by Beijing could be way underestimated.

The spending has made the global community nervous. The U.S., for instance, has shifted its defense strategy to focus more on Asia, though it will cut its overall military outlays by about $487 billion over the next decade.

The white paper says China has continued to be assertive in parts of the Pacific, citing an event last year when it sent out a task force of 11 ships that passed Miyako Island and Okinawa Island. China allegedly has also been operating unmanned aircraft over the Pacific.

The paper also points out that China continues to be involved in long-standing territorial disputes in the resource-rich South China Sea and around the Senkaku Islands in the East China Sea. Chinese government vessels and fishing boats entered Japanese territorial waters near the Senkakus several times last year, the report says.

Morimoto said such an assertive posture isn’t necessarily raising alarm bells in Japan.

Experts say there is an intricate balance dealing with China over the territorial disputes, highlighted by the recent ASEAN regional forum in Phnom Penh where, for the first time in 45 years, no communique was produced due to simmering tensions in the South China Sea.

The paper notes the balance of power between the People’s Liberation Army and the ruling Communist Party has become “more complicated and changing,” saying the PLA might be expanding its clout over territorial disputes and security issues.