(Adds Chinese Foreign Ministry comment)
By Tim Kelly
TOKYO, Sept 27 (Reuters) - China's growing military might has replaced North Korean belligerence as the main security threat to Japan, Tokyo's annual defence review indicated on Thursday, despite signs that Pyongyang could have nuclear-tipped ballistic missiles.
The document's security assessment on China comes after a section on Japan's ally, the United States, the first time Beijing has achieved second place in the Defence White Paper and pushing North Korea into third position.
Russia, deemed by Japan as its primary threat during the Cold War, was in fourth place.
"The reality is that China is rapidly increasing military spending, and so people can grasp that we need more pages," Defence Minister Taro Kono said at a media briefing.
"China is deploying air and sea assets in the Western Pacific and through the Tsushima Strait into the Sea of Japan with greater frequency."
China's Foreign Ministry expressed displeasure with the report.
China will not accept Japan's "groundless criticism" of its normal national defence and military activities, spokesman Geng Shuang said at a press briefing in Beijing.
Japan has raised defence spending by a tenth over the past seven years to counter military advances by Beijing and Pyongyang, including defences against North Korean missiles which may carry nuclear warheads, the paper said.
North Korea has conducted short-range missile launches this year that Tokyo believes show Pyongyang is developing projectiles to evade its Aegis ballistic missile defences.
To stay ahead of China's modernising military, Japan is buying U.S.-made stealth fighters and other advanced weapons.
In its latest budget request, Japan's military asked for 115.6 billion yen ($1.1 billion) to buy nine Lockheed Martin F-35 stealth fighters, including six short take-off and vertical landing (STOVL) variants to operate from converted helicopter carriers.
The stealth jets, U.S.-made interceptor missiles and other equipment are part of a proposed 1.2% increase in defence spending to a record 5.32 trillion yen in the year starting April 1.
By comparison, Chinese military spending is set to rise this year by 7.5% to about $177 billion from 2018, more than three times that of Japan. Beijing is developing weapons such as stealth fighters and aircraft carriers that are helping it expand the range and scope of military operations.
Once largely confined to operating close to the Chinese coast, Beijing now routinely sends its air and sea patrols near Japan's western Okinawa islands and into the Western Pacific.