The powerful sister of North Korean leader Kim Jong-un has unleashed a sarcasm-filled tirade over South Korean President Yoon Suk Yeol's New Year's Day address that unveiled a plan to complete a studier deterrence system with the United States to counter North Korean threats this year.

In a statement late Tuesday night, Kim Yo-jong, a vice department director of the ruling Workers' Party's Central Committee, said that the deterrence plan has again given justification for the North to spur efforts to secure "more overwhelming" nuclear forces.

During the speech, Yoon highlighted his pursuit of "genuine and lasting peace" through strength and laid out a plan to devise an improved deterrence system in the first half of the year.

"(I) greatly welcome with open arms (the fact) that President Yoon plans to continue unique contributions for the rapid ascent of our country's military strength," Kim said in the statement carried by the North's official Korean Central News Agency.

Kim sarcastically accused Yoon of being credited with making security anxiety a part of "everyday life" in South Korea.

Touching on the cross-border policy of Yoon's predecessor, former President Moon Jae-in, she claimed that Pyongyang, hindered by Moon's peace drive, could not do what it had to do for military strength and "wasted" time.

During his presidency from 2017-2022, Moon doubled down on his drive for inter-Korean reconciliation and cooperation, but his efforts stalled following a no-deal Hanoi summit between then US President Donald Trump and the North Korean leader in 2019.

The North has been ratcheting up tensions recently with ballistic missile tests and tough rhetoric against the South and the US.

Concluding the plenary meeting of the Central Committee of the Workers' Party of Korea on Saturday, the North Korean leader put forth the goal of launching three more military spy satellites as well as adding to its nuclear arsenal this year. (Yonhap)