Japan, in its annual defence review, said China's muscle-flexing actions in the East and South China seas are attempts to change the status quo by coercion.
This includes dangerous acts that could have unintended consequences, the Japanese Defence Ministry said in a White Paper that was released yesterday after it was approved by Prime Minister Shinzo Abe's Cabinet.
"China is poised to fulfil its unilateral demands without compromise, which has included making steady efforts to turn these coercive changes to the status quo into a fait accompli," it said in the 484-page paper.
This year's edition devoted much attention to flashpoints in North-east Asia, with the nuclear threat of North Korea presented before China in the document.
China's Defence Ministry reacted angrily to the paper, saying it was "firmly opposed" to the "preposterous comments on China's legitimate defence and military building", which amounted to making excuses for its military expansion and revision of its pacifist Constitution.
The White Paper highlighted a litany of alleged misdemeanours, including one this year where a Chinese naval frigate entered Japan's contiguous zone near a crop of islets in the East China Sea that is claimed by both parties.
China is poised to fulfil its unilateral demands without compromise, which has included making steady efforts to turn these coercive changes to the status quo into a fait accompli.
JAPAN'S WHITE PAPER, on Beijing's actions in the East and South China seas.
Tensions between the two countries over the islets - known as Senkaku in Japan and Diaoyu in China- have been high in recent years.
The paper said: "Recently, China has been intensifying activities near the Senkaku islands, such as its military aircraft flying southwards, closer to the islands."
It added that Japan's Air Self-Defence Force had to scramble fighter jets to counter Chinese aircraft 571 times in fiscal year 2015 - a "dramatic" increase of 23 per cent.
Tokyo last month said the number of scrambles hit a record of 199 times over a three-month period between April and June this year.
The report covered events up till June 30, and thus, did not directly address the July 12 decision by the Arbitration Tribunal on a case brought by the Philippines against China's claims in the South China Sea, which largely favoured Manila.
But it did comment on China's actions in the contested waters, accusing it of "singing the tune of peaceful development on the one hand, but disregarding international laws and norms on the other".
Japan devotes chapter to security legislation in defence review
Japan has for the first time devoted a chapter to its Legislation for Peace and Security in its annual defence review that was approved by the government yesterday.
The law involves reinterpreting the post-war pacifist Constitution to allow Japan's military, the Self-Defence Forces, the right to exercise collective self-defence and go to the aid of ally nations under attack.
The law, passed last September, is of "historical significance and has been highly appraised and favoured by the international community", the white paper said.
"The security environment surrounding Japan has become increasingly severe," it added. "Amid this, enforcing the legislation to ensure and contribute to peace and stability of the regional and international community is more important than ever."
The document noted that countries such as the United States and Australia, and groupings like Asean and the European Union have "strongly supported the measure which is key to strengthening the US-Japan military alliance".
But what was left unsaid is the opposition to the law by China and South Korea, where Japan's actions during World War II still rankle.
Dr Masashi Nishihara, president of Japan's Research Institute for Peace and Security, said: "The situation is that Japan should be more positive in supporting US forces. But the big-picture question is how far can we go?" He expressed concerns over Japan's military might, including a lack of coordination between its navy and coast guard.
The white paper said US military presence in Japan is a way of deterring external threats. But it also said the stationing of US troops on the southern island of Okinawa is unpopular with residents, especially with a spate of crimes involving US personnel, including the rape and murder of a 20-year-old woman in May.
Attempts to relocate a US Marine base to another part of the island have seen protests.
Japan's defence budget for fiscal year 2016 increased marginally by 0.8 per cent to 4.86 trillion yen (S$63.7 billion), due to the purchase of new military equipment and costs involved in hosting US troops.
The paper, comparing the increase in defence budgets over 10 years, said Japan's went up by 1.01 times, lower than the US (1.15 times) and China (3.4 times).
Japan will also be employing more female soldiers in the SDF, and reviewing restrictions over their deployment in certain combat roles, the paper said.
Using satellite imagery of islands within the disputed waters of the South China Sea, it said China has "pressed ahead" with rapid and large-scale land reclamation works on the Spratly and Paracel islands.
Japan, in its paper, urged all countries to act according to the United Nations Convention on the Law of the Sea, and for Asean and China to work towards a code of conduct in the waterway.
Yesterday's paper came a day after the Chinese navy shot dozens of missiles and torpedoes into the East China Sea as part of live-fire drills.
It was also announced last week that China and Russia will hold their annual joint naval exercise in the South China Sea for the first time.
Ms Yuki Tatsumi, a senior associate of the East Asia Programme at the United States-based Stimson Centre, told The Straits Times: "The best Japan can do is to ensure that they have sufficient defence capability to deter China from trying anything too provocative and aggressive, given that China has been outspending Japan in its defence spending."
The paper also highlighted North Korea and terrorism as key threats.
Tokyo suggested that it "could be possible" that North Korea has developed nuclear warheads, given the "technological maturity" of the country's four nuclear tests so far - the latest being in January this year.
It criticised the "continued provocative military actions", saying: "North Korea seems to have been further advancing its overall development of ballistic missiles."
International security expert Tosh Minohara from Kobe University told The Straits Times that North Korea is a "much more viable threat in the short-term" than China.
"China is a mid- to long-term threat because it is wise enough not to use its nuclear arsenal. But North Korea will most likely not hesitate to use it if it finds that its regime is threatened," he said, noting the uncertainty surrounding North Korean leader Kim Jong Un's actions.
In a marked departure from previous editions, the White Paper also said Japan needs to "squarely address" global terrorism "as its own challenge". Past editions had said only that Japan "should not be indifferent" to the threat.
Seven Japanese aid workers were slain in a cafe siege in the Bangladesh capital of Dhaka last month.