"Suspending uranium enrichment has no logic behind it and it is not acceptable and the continuation of negotiation will not be based on suspension," Iranian government spokesman Gholam Hossein Elham told reporters.
His comments come a day after Iranian Foreign Minister Manouchehr Mottaki indicated Tehran is willing to hold talks over its nuclear programme.
"We have informed the group of 5+1 countries of our readiness to negotiate over our own peaceful nuclear activities," he said
"The package put forward by the 5+1 countries is under consideration in Tehran and we will give the response at an appropriate time," he added.
A week ago, European Union foreign policy chief Javier Solana presented a new offer to Mottaki on ending the six-year standoff over Iran's nuclear drive, offering economic and trade incentives.
It was made on behalf of Britain, China, France, Germany, Russia and the United States.
On Thursday President Mahmoud Ahmadinejad said that the "new game" of the West in the nuclear standoff with Iran would end in humiliation.
"The nuclear issue has ended from our point of view. Recently they have started a new game — by testing us — but this will result in no achievement for them except humiliation," he said.
The West fears Iran could use uranium enrichment to make an atomic bomb although Tehran insists it wants only to generate nuclear energy for peaceful purposes.
