North Korean leader Kim Jong Un urged his party to "accelerate" war preparations including its nuclear programme, state media said on Thursday.

The comments came just a week after Kim warned Pyongyang would not hesitate to launch a nuclear attack if "provoked" with nukes.

Kim made the comments at the North's ongoing year-end party meeting, where he is expected to unveil key policy decisions for 2024.

Kim asked the party to "further accelerate the war preparations" across sectors, including nuclear weapons and civil defence, Pyongyang's official Korean Central News Agency reported.

He also stressed that the "military situation" on the Korean peninsula had become "extreme" due to "unprecedented" anti-North confrontations with Washington.

Seoul, Tokyo and Washington have ramped up defence cooperation in the face of a record-breaking series of weapons tests by Pyongyang this year and recently activated a system to share real-time data on North Korean missile launches.

Earlier this month, a US nuclear-powered submarine arrived in the South Korean port city of Busan, and Washington flew its long-range bombers in drills with Seoul and Tokyo.

Pyongyang this year successfully launched a reconnaissance satellite, enshrined its status as a nuclear power in its constitution, and test-fired the most advanced intercontinental ballistic missile in its arsenal. (AFP)