"Even if some officials are taking it easy on gaining the technology, the people will not give up," Ayatollah Ahmad Jannati said in a Friday prayer sermon in Tehran.
"We are resolute. It is worth achieving it at any cost," said Jannati, who head the powerful Guardians Council -- a body that screens all of the Islamic republic's laws and candidates for public office.
"Nuclear technology is the issue of the day, and neither our officials nor our people will give up this scientific growth," he said.
Jannati also reasserted Iran's desire to be independent in its bid to generate nuclear power, including in fully mastering the sensitive nuclear fuel cycle.
"We are now begging Western nuclear know-how by importing what we lack in this field. Once we achieve the technology, we will no longer be in a position where we have to ask," he said.
Iran is currently top of the agenda for the International Atomic Energy Agency (IAEA), which is probing allegations the country is using power generation as a cover for a secret weapons drive.
Tehran insists its programme is solely aimed at meeting the future energy needs of a burgeoning population and freeing up its oil and gas resources for export.