Vienna: The head of the UN atomic watchdog said yesterday Iran's barring of experienced nuclear inspectors was hampering the agency's work in the Islamic state, but Tehran flatly rejected the accusation.

Signalling a desire for continuity at the International Atomic Energy Agency at a time of strained ties with Tehran, Director-General Yukiya Amano named a senior Iran expert and IAEA insider as its new top investigator, diplomats said.

Herman Nackaerts, who now oversees inspections in Iran and elsewhere in the Middle East as well as South Asia and Africa, will succeed former boss Olli Heinonen as head of the IAEA division which verifies that nuclear work in member states worldwide is not being diverted for military use.

"There was no dissent," a diplomat said on the sidelines of a closed-door meeting of the IAEA's 35-nation governing board, where Amano earlier criticised Iran over the barred inspectors. Heinonen, a Finn, resigned as deputy director-general in charge of global nuclear safeguards in July for personal reasons after nearly 30 years at the Vienna-based body.

Nackaerts, 59, from Belgium, will take up the top inspection job in the midst of a row over Iran's refusal to admit some inspectors.

In June Iran barred two inspectors who had worked in the country. Their nationalities have not been disclosed. Tehran also cancelled access for a high-ranking Middle East inspector in 2006 and objected to a number of other inspector designations in the past. "I learned with great regret about Iran's decision to object to the designation of two inspectors who recently conducted inspections in Iran," Amano said in a speech to the board.

Iran has accused the two of distributing "false" information about its nuclear activities. But Amano told the board he had full confidence in their "professionalism and impartiality".

Categoric rejection

"Iran has not provided the necessary cooperation to permit the Agency to confirm that all nuclear material in Iran is in peaceful activities," the veteran Japanese diplomat said, according to a copy of his speech made behind closed doors. "Iran's repeated objection to the designation of inspectors with experience in Iran's nuclear fuel cycle and facilities hampers the inspection process," he added.

Ali Asghar Soltanieh, Iran's ambassador to the IAEA, told reporters: "I categorically reject this statement" by Amano that Tehran's behaviour was hindering inspection activity. Soltanieh, who criticised the IAEA's latest report on Iran as unbalanced and as damaging to its credibility, said the IAEA had more than 150 inspectors at its disposal for Iran.