A nuclear war is close to breaking out in the Korean peninsula, North Korea's ambassador to the United Nations warned on Tuesday.

Speaking on the same day that UN chief Antonio Guterres warned of a new nuclear arms race, Ambassador Kim Song blamed the situation to actions of the United States over the past year.

He pointed to the recent formation of the Nuclear Consultative Group, through which the United States hopes to integrate its nuclear capacity better with South Korea's conventional forces, with the two allies increasing information sharing and contingency planning.

Kim said the group was "committed to the planning, operation and execution of a preemptive nuclear strike against the DPRK," the official name of the North, the Democratic People's Republic of Korea.

"The US is now moving on to the practical stage of realizing its sinister intention to provoke a nuclear war by frequently dispatching strategic nuclear submarines and strategic nuclear bombers carrying nuclear weapons in and around the Korean peninsula for the first time in decades," he added.