The new tactical ballistic missile is reportedly capable of carrying a 4.5-ton super-large warhead.
It comes as the Russian president makes a rare visit to the reclusive state.
The trip is Putin's first to Pyongyang in 24 years.
The streets of Pyongyang were decked out with Russian flags and posters of Putin ahead of his arrival.
The message came amid speculation Putin will visit North Korea and Vietnam in the coming weeks.
Residents living near the border are now on edge.
The nation issued a warning over surveillance.
Pyongyang called on New Zealand and other countries to immediately stop their "blatant military intervention in the Asia-Pacific".
Kim Yo Jong says the country will protect its sovereignty and regional peace.
