Pyongyang has repeatedly insisted it will not abandon its nuclear arsenal, portraying it as essential to deterrence, with Kim Yo Jong, the powerful sister of leader Kim Jong Un calling the policy a "line of no retreat" earlier this month.

The North's statement came after a trilateral meeting between South Korea, Japan and the United States in Tokyo on Friday, at which the allies reaffirmed their commitment to the "complete denuclearisation of the Korean Peninsula", according to Seoul's foreign ministry.

"The US and its vassal forces' meaningless rhetoric against the DPRK... can never affect the irreversible position of the DPRK as a nuclear weapons state," the unnamed spokesperson said in a statement published by the official Korean Central News Agency on Sunday, using the acronym for the North's official name.

"The 'denuclearisation' is an irreversibly finalised matter," the official added.

The spokesperson also cited Washington's sales of weapons systems to Seoul and Tokyo as justification for Pyongyang's pursuit of its nuclear programme, describing it as " a strong security guarantee for regional stability and peace".

"No matter how hard the US, Japan and the ROK may quibble, they will never change the present position of the DPRK as a nuclear weapons state," the official said, referring to the South by the acronym of its official name.

North Korea has accelerated its nuclear weapons programme since talks with Washington broke down in 2019, when a summit between Kim and US President Donald Trump in Hanoi ended without agreement.

In a possible reference to the failed negotiations, the spokesperson said "no one can recover the 'denuclearisation' permanently missed in the trend of the times".

Kim recently hosted China's President Xi Jinping in Pyongyang, after the Chinese leader held back-to-back summits in Beijing with Trump and Putin.

Neither side made any mention of denuclearisation, according to their official media reports.