Iran's parliamentary speaker Ali Larijani told former German Chancellor Gerhard Schroeder in Teheran on Saturday that it is impossible to deprive Teheran of nuclear technology for peaceful uses.
Mr Larijani is a former nuclear negotiator for Iran.
The International Atomic Energy Agency said on Thursday Iran is continuing to enrich uranium, but has slowed the expansion of its enrichment activities.
The agency said Iran had built up a stockpile of nuclear fuel.
An IAEA report said 3,936 centrifuges were actively enriching uranium. Another 1,476 were undergoing tests without nuclear material in them and 125 more had been installed but remained stationary.
Western countries suspect the nuclear programme is aimed at acquiring atomic weapons. Tehran denies this, saying it is for domestic energy use.
Mr Schroeder is on an unofficial visit to Iran and has met President Mahmoud Ahmadinejad.
The Mehr news agency quoted the former German leader as saying Iran has an opportunity to ease tensions with the West.