Kim In-ryong told reporters.
The claim is being made at a time when speculation is rising over the goal of CIA Director Mike Pompeo's recent visit to Seoul, where he may have met with a high-level defector, according to the Washington Free Beacon.
Speaking at the United Nations headquarters in New York City, the Democratic People's Republic of Korea's deputy U.N. ambassador flatly denied Pyongyang played a part in last week's unprecedented cyberattack, dismissing suspicions raised recently by security researchers in the US and overseas.
Moon, a strong supporter of former Presidents Kim Dae-jung and Roh Moo-hyun's Sunshine Policy of engagement of the North, kept open the possibility of an inter-Korea summit but said it could only be held when Pyongyang "changes its behavior".
He said North Korea "probably learned a lot" from last weekend's test.
U.S. Ambassador to the United Nations Nikki Haley raised concern on Friday about an application by North Korea to patent a process to produce sodium cyanide, which can be used to make the nerve agent Tabun and is also used in the extraction of gold.
"I am sure that more defections of my colleagues will take place, since North Korea is already on a slippery slope", Thae had said in January.More news: United States will not re-impose sanctions on Iran's Nuclear Programme
The UN Security Council was swift to condemn the test but North Korea's director of Asian affairs, Pak Jong-hak, insisted Tuesday that Pyongyang would not be deterred.
North Korea's deputy U.N. envoy said on Friday that the United States needed to roll back its "hostile policy" toward the country before there could be talks between the pair.
"Until the USA and its followers make a right choice, we will further produce sophisticated and diversified nuclear weapons and striking means and push to prepare for necessary tests", Pak said according to the North's state-run KCNA news agency.
All 15 members of the Security Council including North Korea's closest ally China called the launch a violation of United Nations sanctions and vowed to take new measures, including additional sanctions.
North Korea, also known as the Democratic People's Republic of Korea (DPRK), has vowed to develop a missile mounted with a nuclear warhead that can strike the mainland United States, saying the program is necessary to counter US aggression. It noted that "patent applications are not covered by the provisions of U.N. Security Council Resolutions".
Trump warned this month that a "major, major conflict" with North Korea was possible, and in a show of force, sent the USS Carl Vinson aircraft carrier strike group to the Sea of Japan to conduct drills with South Korea and Japan.
The "relatively low compromise rate of South Korea, Japan, and the US runs contrary to every attack ever authorized by Pyongyang", reported Cybereason, a Boston-based security firm. She urged other countries to sever ties with Pyongyang.