Her remarks come after the top diplomats of South Korea, Japan and the United States issued a statement on the sidelines of a NATO meeting last week in which they "reaffirmed their resolute commitment to the complete denuclearisation" of the isolated state.

In a statement published Wednesday by the official Korean Central News Agency (KNCA), the sister of ruler Kim Jong Un said that any discussion of convincing the North to give up its nuclear weapons is "nothing but a daydream that can never come true".

"If anyone openly talks about dismantling nuclear weapons... it just constitutes the most hostile act of denying the sovereignty of the DPRK," Kim Yo Jong said Tuesday.

"It only fully exposed the uneasiness of the US, Japan and the ROK, in a desperate plight of having to talk about 'denuclearization' in chorus," she said, referring to the South by its official name.

The statement was Kim's second in a little over a month.

In early March, she condemned Washington over the visit of a US Navy aircraft carrier to the South Korean port of Busan, accusing US President Donald Trump's administration of "carrying forward the former administration's hostile policy".

During his first term, Trump became the first sitting US president to meet a North Korean leader when he held talks with Kim Jong Un in 2018 in efforts to reach a deal on denuclearisation.

Since taking office a second time in January, he has referred to the North as a "nuclear power".

Pyongyang has ramped up efforts to further enhance its nuclear and military capabilities since Trump and Kim's second summit in Hanoi collapsed in 2019.