Ivanov's spokesman was quoted on Friday by the agency, as saying: "There was no such conversation."
An Iranian diplomat on Thursday had said Ivanov and Ali Larijani Iran's chief nuclear negotiator had agreed to hold talks on the proposal in a telephone conversation.
The proposal, which is backed by Washington and the European Union, involves the creation of a joint Iranian-Russian company to enrich uranium in Russia.
The plan has been put forward by Moscow in a bid to allay international concerns that Iran could manufacture highly enriched uranium on its own soil to build atomic weapons.
Iran says it only wants to enrich uranium to a low grade, suitable for use in atomic power reactors.
Iranian officials had previously said they would reject any plan which denied Iran the right to build its own uranium enrichment facilities.
But, in a sudden change of tone, a senior official said on Wednesday Tehran would "seriously and enthusiastically" study the Russian plan.