"With the opening of this naval base a new line of defence has been created east of the Strait of Hormuz," Admiral Habibollah Sayyari was quoted as saying by the Fars news agency.
"We can prevent the entry of any enemy naval units into the strategic Persian Gulf area if need be," he said, adding that the base was located in the port town of Jask on the Sea of Oman.
"The army needed new bases on the Sea of Oman given the presence of forces from outside the region in the waters around Iran," he added.
An estimated 40 percent of the world's oil passes through the narrow channel between Iran and Oman, and Tehran has warned in the past it could block the waterway if it comes under attack over its controversial nuclear programme.
Iran frequently stages war games in the Gulf, showing off an array of home-produced weaponry including missiles which it says are capable of targeting vessels along the entire seaway.
The United States and its regional ally Israel, which accuse Iran of seeking atomic weapons, have never ruled out a military option to thwart the Islamic republic's nuclear drive.
Iran vehemently denies the allegation, insisting that its nuclear programme is strictly aimed at peaceful ends.
