North Korea fired its most powerful ballistic missile yet last week, the solid-fuel Hwasong 18 intercontinental ballistic missile, the latest of a string of launches this year.

Seoul and Washington have ramped up defence cooperation in response to the North's weapons tests, staging joint military exercises with advanced stealth jets and US strategic assets.

They will hold their inaugural meeting of the Nuclear Consultative Group (NCG) in Seoul on Tuesday, which, according to the presidential office in Seoul, is aimed at "bolstering nuclear deterrence against North Korea".

Kim Yo Jong warned that a strengthened extended deterrence system and military alliance will only further alienate the North from dialogue.

"It is a daydream for the U.S. to think that it can stop the advance of the DPRK and, furthermore, achieve irreversible disarmament through the interim suspension of joint military exercises, halt to the deployment of strategic assets and the reversible sanction relief," she said in a statement carried by the Korean Central News Agency.

For now, the best way to ensure peace and stability was to deter the United States with force "rather than solving the problem with the gangster-like Americans in a friendly manner," Kim Yo Jong said.

North Korea accused a US spy plane of violating its airspace last week and condemned Washington's plans to deploy a nuclear missile submarine near the Korean peninsula.

Washington said in April one of its nuclear-armed ballistic submarines would visit a South Korean port for the first time in decades, without specifying a date.

South Korea and the United States are set to start their major annual joint military exercises next month.