North Korean leader Kim Jong-un has said the Korean peninsula will be engulfed by ''massive nuclear disaster'' if war breaks out there again, warning the US it will not be safe in the event of a conflict.

''If the war breaks out again in this land, it will bring about a massive nuclear disaster and the US will never be safe,'' Kim said in his New Year message, broadcast on state television.

North Korean leader Kim Jong-un. Credit:Reuters

''We are faced with a dangerous situation in which a small, accidental military clash can lead to an all-out war.''

Mr Kim added he would not beg for peace and vowed to protect the impoverished but nuclear-armed North with strong self-defence measures against enemies.