The Paris agency indicated Iran's oil exports fell to 860,0000 barrels per day in September -- far below the December 2011 level of 2.2 million bpd, the Azerbaijan news agency Trend reported.
The IEA said economic sanctions slapped on Iran by the European Union and the United States over its uranium enrichment program had succeeded in narrowing its list of foreign oil customers to China, India, South Korea, Japan and Turkey.
Khatibi, however, refuted the report Saturday in comments to the Iranian Students' News Agency.
"Iran's oil exports are the same as previous months and the situation is stable," he said.
The IEA figures also indicated Iranian oil production was down 220,000 bpd last month compared to the August mark, dropping to the lowest levels since 1988, The New York Times reported.
At 2.63 million barrels per day, the IEA's figures put Iran's production close to its all-time low mark of 2.49 million barrels per day seen 24 years ago, Organization of Petroleum Exporting Countries figures showed.
Khatibi, also Iran's representative to OPEC, said his nation was finding new markets for its oil.
"The market for Iranian oil is beyond the mentioned countries ... We are always exploring new markets but we don't publicize them much because it may be detrimental," Khatibi told ISNA.
Iran's Mehr News Agency quoted a member of the Iranian Parliament, Mohammad Ali Abdollahzadeh, as saying oil exports have actually increased by 70 percent since the Iranian calendar month of Shahrivar, which started Aug. 22.
Khatibi asserted last month Iran's oil production is still putting it near the top of the OPEC list, showing continued strength despite the Western sanctions.
"We are responsible toward those figures we present directly to OPEC secretariat, the figures that show Islamic republic of Iran maintain its position as the second biggest oil producer in OPEC," Khatibi told the oil ministry's news service, known by its Persian initials SHANA.
He didn't offer specific figures, however. OPEC ranks Iran third in terms of oil reserves among member states.
Tehran in September announced that private companies delivered oil to the foreign market for the first time. An agreement with unspecified entities allows private companies to export about 20 percent of the country's total oil deliveries designated for the international market.
In terms of crude oil prices, Khatibi said prices of around $100 per barrel were nominal. Concerns expressed from major economies like the United States, he added, were likely a result of the presidential campaign season.
The EU and United States this summer hit Iran with a round of sanctions targeting its energy and financial sectors, barring other countries from buying its oil or dealing with the Central Bank of Iran.
Iran's currency, the rial, has plunged 40 percent compared with the dollar in recent weeks, sparking acute inflation within the country, Western experts have said.