China’s growing military might has replaced North Korean belligerence as the main security threat to Japan, Tokyo’s annual defence review reveals, 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.

“It is a reflection of the fact that only United States and China can project their influence globally,” a Ministry of Defence official told a news briefing on Thursday.

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 a series of short-range missile launches 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 US-made stealth fighters and other advanced weapons.

In its latest budget request, Japan’s military asked for 115.6 billion yen ($1.58 billion) to buy nine Lockheed Martin F-35 stealth fighters, including six short take-off and vertical landing variants to operate from converted helicopter carriers.

The stealth jets, US-made interceptor missiles and other equipment are part of a proposed 1.2 per cent rise in defence spending to a record 5.32 trillion yen ($73 billion) in the year starting April 1.

By comparison, Chinese military spending is set to rise this year by 7.5 per cent to about $US177 billion ($262 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.

China has frequently rebuffed concerns about its military spending and intentions, including a ramped up presence in the disputed South China Sea, and says it only desires peaceful development.

The Defence White Paper said Chinese patrols in waters and skies near Japanese territory are “a national security concern”.

The paper downgraded fellow US ally, South Korea, which recently pulled out of an intelligence sharing pact with Japan amid a spat over their shared wartime history. The move could weaken efforts to contain North Korean threats, analysts said.

Other partners, including Australia, the Association of Southeast Asian Nations (ASEAN) and India, feature more prominently in the defence paper.

– AAP