"We are ready to cooperate fully and closely with IAEA," he told CNN, while stressing that "ambiguities have to be removed" before Tehran can sign an additional protocol to the nuclear Non-Proliferation Treaty (NPT) as demanded by the United States and the rest of the international community.
Kharazi said Iran did not possess highly-enriched uranium at its sites.
That was a denial of the findings of a confidential UN report which said inspectors had found two different types of highly-enriched nuclear particles at facilities in Iran not needed in civilian atomic programs, according to a Western diplomat in Vienna.
Kharazi explained that "the components that we have imported from outside have been contaminated." He said it was a matter for IAEA inspectors to verify and urged observers not to rush to conclusions. "It is a matter of technicians and should not be politicized."
Kharazi pointed to Iranian gestures of good will, saying Tehran had allowed IAEA inspectors to take samples at facilities and had decided to open negotiations on signing the protocol.
"These are two major steps that have been taken and have been appreciated by the IAEA director general (Mohamed ElBaradei) in his (September) report."
He reiterated that it was "the legitimate right of Iran to have access to nuclear technology for peaceful purposes."
On Tuesday, IAEA spokesman Mark Gwozdecky said Iran had signaled it was ready to move towards signing the additional protocol and hailed this as a positive step.
The Iranian government for its part confirmed that it was open to signing the protocol but first wanted "total" guarantees that IAEA inspectors would not be given complete freedom of movement and would not violate military secrets.
"We have not decided when" to make the decision, but "we will undertake nothing without total guarantees," government spokesman Abdollah Ramezanzadeh told reporters here.
From September 8-11, the IAEA board of governors is to gather in Vienna to review the most recent report on Iran's nuclear program. The board is capable of referring Iran's case to the UN Security Council.
The report also says Iran admitted it had tried to import centrifuge material" and that it started a heavy water programme in the 1980s, a Western diplomat in Vienna said. Heavy water is used for reactors that produce plutonium, a material that can be used to make nuclear weapons.
In July, the European Union joined its voice to the United States and expressed "growing concern" about the nature of Iran's nuclear program, pressing Tehran to sign the additional protocol.
It said it would review its ties with Tehran, with which it is negotiating a key trade pact, following the IAEA board of governors meeting.
EU foreign policy chief Javier Solana is to travel to Iran Friday for talks including the thorny issue of Tehran's nuclear capabilities, a spokesman said in Brussels.
His trip is to discuss the state of negotiations on a trade and cooperation accord between Tehran and the European Union, which backs constructive engagement with Iran rather than the isolation policy favoured by Washington.
"They will discuss all the political questions linked to negotiations on concluding an accord between the EU and Iran. That means notably the nuclear issue and human rights," said an EU official.