"The missile has new technical aspects and has a unique tactical capacity," he said.
"Since the surface-to-surface missile has no wings, it has a lot of tactical power, which also reduces the chances of it being intercepted."
Vahidi's announcement came a day ahead of the scheduled launch of Iran's first nuclear power station after a 40-year delay.
The Russian-built power plant, located in the southern Iranian port city of Bushehr, is due to be launched on Saturday, when engineers are to begin loading uranium-packed fuel rods into the reactor.
Russia had agreed in 1995 to build the Bushehr plant on the site of a project begun in the 1970s by Siemens, a German firm, but delays have haunted the $1bn project amid the standoff over Iran's disputed nuclear enrichment programme.
The US has criticised Russia for pushing ahead with the project, saying Iran should prove it is not developing weapons first.
But Russia has said the Bushehr plant is monitored by the UN's International Atomic Energy Agency and has no link with Iran's uranium enrichment programme.
Western countries continue to accuse Iran of seeking to acquire a nuclear weapon under the guise of its civilian nuclear programme.
In June, the UN Security Council approved a fourth round of military and financial sanctions against Iran over its nuclear programme, which included an arms embargo, financial controls, an asset ban on Iranian companies and a travel freeze on individuals.
Tehran insists its programme is entirely peaceful and that it needs nuclear energy for a rapidly expanding population whose fossil fuels will eventually run out.
If started, Bushehr will have an operating capacity of 1,000 megawatts.
Iran, the world's fifth oil producer, has said it wants to build a network of nuclear power plants with a capacity of 20,000 megawatts by 2020 to enable it to export more of its large oil and gas supplies.