Moon, whose parents were refugees from North Korea, won the presidential election last month and had campaigned on rebooting Seoul's tough approach to Pyongyang.
A former human rights lawyer, Moon's approach is different from that of his predecessor, Park Geun-hye, a conservative who was critical of the effectiveness of a so-called Sunshine Policy approach that included humanitarian aid to North Korea and cooperation on projects such as the Kaesong Industrial Park.
"North Korea must give up its nuclear development and find ways to work with the international community," Moon said. "North Korea's decision to give up nuclear weapons will be a symbol showing its determination to implement what has been agreed between the South and the North."
North Korea has test-fired at least 10 ballistic missiles this year, including new midrange missiles that can carry nuclear warheads. The hermit regime's 33-year-old leader, Kim Jong Un, has been in charge since 2011 and conducted more ballistic missile tests and twice as many nuclear weapon tests as his father and grandfather did during their rule.
North Korea's Rodong Sinmun newspaper Thursday said that advancements in the country's missile and nuclear weapons programs have led to the regime becoming a "dignified nuclear and rocket power" and added that Pyongyang stands "open" to reunification and engaging in "bringing about a great turn and change in the north-south relations."
The North Korean paper held out hope that the new president of South Korea would help reduce tensions on the Korean Peninsula. It also blasted the past nine years of conservative leadership in South Korea, charging they "valued cooperation with outsiders more than the nation's interests and openly pursued the policy of submitting to the U.S."
Meanwhile, Seoul's Korea Herald newspaper reported that the North Korean leader is "extremely nervous" about the possibility of being assassinated. It cited comments attributed to a South Korean intelligence official who briefed national lawmakers in Seoul on Thursday.
"Due to concerns over potential airstrikes and assassination attempts, the young tyrant prefers to move at dawn and uses his subordinates' cars, such as a Lexus car, not his own Mercedes-Benz 600," the paper reported.
As a result, the report added that the North Korean leader has curtailed his public activities significantly. Then again, it said the change could be a reflection of a dictator now "confident about his grip on the communist state."
Watch: US sanctions over North Korea arms