A statement issued by state news agency KCNA by a vice director general of the Department of Japanese Affairs of the North Korean foreign ministry said that "it can be said that (Shinzo) Abe is the only one idiot in the world and the most stupid man ever known in history."
Pyongyang also made a veiled threat to fire one towards Japan, Xinhua news agency reported.
The statement added that the Japanese prime minister "fails to tell one thing from another" and that the "underwit" is "excluded from international politics."
It went on to describe him as the "most stupid person ever known in history" as well as a "perfect imbecile and a political dwarf without parallel in the world" as well as "a dog seized with fear."
It also accused the conservative Japanese politician of trying to thwart the stalled talks on denuclearization with the United States with his statements and hinted that "Abe may see what a real ballistic missile is in the not distant future and under his nose."
On Thursday, North Korea fired two projectiles from a multiple launch rocket system that fell into the Sea of Japan (known as the East Sea in both the Koreas) but outside Japan's Exclusive Economic Zone.
Abe, who had previously described such projectiles as ballistic missiles, other members of his Cabinet and Japanese defence ministry officials said that projectiles fired by North Korea on Thursday were not mere rockets.
Tokyo's statements are in line with what several experts are saying about the regime's rocket launchers, which is that the system, with four 600-millimetre launch tubes mounted on a mobile platform, is the closest thing to a ballistic missile without actually being one.
The only thing technically differentiating it from a short-range ballistic missile is the lack of a guidance system.
The system is also mobile, which makes it harder to detect, and the latest test shows an improvement in the interval between the two missiles (about 30 seconds), although it is still not a match for the rocket launchers of the US or China, which are capable of firing every 5 to 6 seconds.
( With inputs from IANS )