Replying to a question about this possibility, Shamkhani said, "Our needs are assured in the ballistic field and, for the moment, we do not feel the need to change anything."
Last year Iran equipped its military with Shahab 3 missiles. The missile is believed to be derived from technology acquired from North Korea and be capable of carrying a 1,000 kilogramme (one-ton) warhead at least 1,300 kilometres (800 miles) -- bringing Iran's arch-enemy Israel within range.
Shahab is Farsi for "meteor" or "shooting star".
Shamkhani, speaking as he left the weekly cabinet meeting, denied any plans to produce a Shahab 4.
"We have nothing called Shahab 4 and the question (of such a missile) has never existed," he said.