The report, which the German weekly Der Spiegel released in advance of its publication on Monday, said the man was ordered to leave the country in July, but the case had not been disclosed until now.
The German Foreign Ministry declined to comment on the report.
The diplomat, an attaché at Iran's embassy in Berlin, was reported to have been in contact with a specialist firm in the southern German state of Bavaria.
"The consular attaché Mohraramalai D. made contact with a Bavarian firm of specialists, apparently trying to buy a piece of equipment which could also be used in uranium enrichment," the magazine said.
What kind of enrichment?
The magazine did not say whether the component could have been used for high-grade enrichment, for bomb material, or low-grade enrichment, which Iran says it carries out to make power plant fuel.
But it quoted a German government report which said that Iran "keeps trying intensively to procure military goods and technology of all kinds from western industrial states."Uranium exists naturally as an ore. For it to be used as a source of nuclear energy or in atomic explosions, scientists need to separate out two of its isotopes, uranium-238 and uranium-235, and boost the concentration of the latter, highly fissile, isotope. This process is called enrichment.
Western nations have been calling on Iran to halt uranium enrichment, which they fear could lead to it making atomic weapons. Tehran, on the other hand, claims its nuclear program is for peaceful purposes.
Renewed sanctions warning
EU leaders reiterated on Friday their support for possible additional sanctions against Iran if it fails to give up nuclear enrichment work.
A joint statement from leaders of the 27-member block meeting in Brussels called on Iran to provide "full, clear and credible answers" to the U.N. International Atomic Energy Agency (IAEA) to resolve questions about its nuclear activity.
They added that the council of member states "reiterates its full support to the work in the UN Security Council to adopt further measures" and said a decision would be taken at the next meeting of EU foreign ministers due on Jan. 28, in the light of upcoming decisions in the UN Security Council.
The EU warning came despite a US National Intelligence Estimate (NIE) report earlier this month claiming Iran had halted its nuclear weapons program in late 2003. NIE cited "moderate confidence" that the program had not been restarted as of mid-2007.
Tehran could have the technical ability to build a nuclear weapon between 2010 and 2015, but "we do not know if it currently intends to develop nuclear weapons," the report stated.