State television said on Saturday Iran's Revolutionary Guards would test fire the missile during military manoeuvres being observed by Ayatollah Ali Khamenei, after firing short- and medium-range missiles on Friday.
"The most important part of today's programme consists of the firing of a long-range missile on fictitious enemy positions," the television said.
Iranian media have been giving extensive coverage to the manoeuvres in the western part of the country.
The report gave no details on the range or capabilities of the missile.
In August, Tehran tested an enhanced version of its medium-range Shahab-3 missile, which is derived from the North Korean No-dong missile reportedly capable of carrying a 1000kg warhead.
The Shahab-3 was deployed with the Revolutionary Guards air arm in July 2003.