The UN nuclear agency insisted on Tuesday that Iran must address concerns about suspected bomb research, saying it was ready for talks and avoiding any mention of Tehran's allegation that "terrorists" may have infiltrated the Vienna-based agency.

The International Atomic Energy Agency (IAEA) issued a statement on a meeting between IAEA chief Yukiya Amano and Iranian nuclear energy head Fereydoun Abbasi-Davani on Monday, which was held just hours after Abbasi-Davani sharply criticised the agency in a speech to its annual assembly.

Amano said it was essential for Iran to cooperate with his inspectors to clarify concerns about possible military dimensions to its nuclear programme, a charge Tehran rejects.

He told Abbasi-Davani that the IAEA "is committed to continued dialogue with the Islamic Republic of Iran and expressed the readiness of agency negotiators to meet with Iran's in the near future", the statement said.

The UN agency has been seeking to resume a long-stalled investigation into Iran's atomic activities, but talks that began in January have made little headway.

In a sign of the depth of mistrust between Iran and the IAEA, Abbasi-Davani accused the UN agency of a "cynical approach" and mismanagement in his speech on Monday.

He said power lines to Iran's Fordow underground enrichment site were blown up a month ago, and that an IAEA inspector had asked for an unannounced visit to the site a day later and that "terrorists and saboteurs might have intruded" into the agency.

Abbasi-Davani did not say who he believed was behind the attacks. Iran has often accused Israel and its Western foes of trying to damage its nuclear work.

Western diplomats privately dismissed the Iranian allegations against the IAEA as an attempt to divert attention from Tehran's stonewalling of the agency's inquiry.

"Iran's accusations against the IAEA are a new low. Increasingly cornered, they are lashing out wildly," said nuclear proliferation expert Mark Fitzpatrick of the International Institute for Strategic Studies think-tank.

Fordow worries the West most as it produces uranium of 20 per cent fissile purity, more than for power plants and only a short technical step from the 90 per cent needed for a weapon.

The IAEA said Amano had stressed in his meeting with Abbasi-Davani the "importance of early clarification of outstanding issues" related to Iran's nuclear programme.

"It is essential for Iran to extend its full cooperation to the Agency... a structured approach to clarify all issues related to Iran's nuclear programme, including those related to possible military dimensions, needs to be agreed and implemented as soon as possible," Amano said.

"I sincerely hope we will be able to move swiftly towards concrete progress," Amano told Abbasi-Davani. - Reuters