The presidential office on Thursday rejected former President Moon Jae-in's call for reviewing its approach to unification with North Korea, saying the previous government's dialogue-focused peace initiative is "unrealistic."

A senior presidential official who accompanied President Yoon Suk Yeol on a trip to the Czech Republic made the remark after Moon criticized the Yoon administration's hard-line policy on North Korea and called for efforts to ease inter-Korean tensions.

The official said the Moon administration failed to effectively implement measures to ensure peace on the Korean Peninsula while prioritizing talks with North Korean leader Kim Jong-un and pushing for declaring a formal end to the 1950-53 Korean War, which ended in a truce.

"Didn't they lobby the United States and the world that 'the war is over, and peace has arrived?'" the official told reporters in Prague. "It is a matter of how to build peace."

The official criticized that the previous government lacked efforts to build strong deterrence against North Korea's threats, claiming that it mishandled the deployment of the US THAAD missile defense system and paid little attention to establishing extended deterrence in coordination with the United States.

The THAAD system was installed in Seongju, some 215 kilometers southeast of Seoul, in 2017 but held the status of a "temporary" installation for years due to an environmental impact assessment requirement.

"Pursuing peace only through dialogue with North Korea is unrealistic," the official added.

Last month, Yoon announced a unification doctrine that pursues peaceful unification with the North based on liberal democracy and suggested a working-level dialogue channel between the two Koreas.

North Korea has not responded to the offer and has continued to send trash-carrying balloons across the border in recent months. (Yonhap)