Khamanei also lashed out at “superficial and narrow-minded” critics who have warned the drive could come at too great a cost for Iran, saying such comments only served to encourage the enemy.
“Nuclear energy is the future and destiny of the country,” state television quoted him as saying in a speech in Tehran.
The television said Khamenei “criticised some who, with superficial and narrow-minded views, say that nuclear energy is not necessary for the country at this cost.”
He said Iran’s huge oil and gas reserves “would not last forever”.
“If a nation does not care about the future of its energy, it must remain dependent on the domineering powers,” he said in allusion to Western governments.
Iran is the world’s fourth biggest producer of crude and has the second largest natural gas reserves after Russia, although it lags well behind other countries in terms of gas exports.
“The reason for the powers’ objection to the Iranian nation’s achievement of nuclear energy, even though they use it themselves, is that they want to take hold of the destiny of the world’s energy,” said Khamenei.
A widely reported study published in December by the academic Roger Stern of Johns Hopkins University in the United States said Iran could soon face its own energy crunch owing to failing infrastructure and lack of investment.
Khamenei’s intervention comes as pressure mounts from Western countries for Iran to suspend uranium enrichment, a process that can be used both to make fuel for nuclear power stations and the core of an atomic weapon.
But there has also been an intensification of diplomacy in recent weeks, with chief nuclear negotiator Ali Larijani holding talks with EU foreign policy chief Javier Solana while attending the Munich security conference.
The United States accuses Iran of seeking a nuclear weapon, a charge denied by Tehran which insists its atomic programme is peaceful and that it has every right to the full nuclear fuel cycle.
Although Washington has said it wants the nuclear standoff resolved through diplomacy, it has never ruled out military action to thwart Iran’s atomic drive.
“In this path, one should not be frightened by the enemy… One should be strong against the enemy. Any expression of weakness will make the enemy bolder,” said Khamenei.
Voices have been raised in parliament and the press in recent weeks over the confrontational stance of President Mahmoud Ahmadinejad on the nuclear issue, which they said has come at too great a diplomatic cost.
“Some people with their comments exaggerate problems that do not exist in the country. This encourages the enemy. This is wrong,” said Khamenei.
