Western envoys gave Iran's new ambassador to the UN atomic agency a frosty welcome Wednesday, saying Tehran's new government should waste no time proving to the world it does not want the bomb.

Speaking at a meeting of the International Atomic Energy Agency's board of governors, US envoy Joseph Macmanus said Iran was refusing to comply with UN Security Council and IAEA resolutions demanding it suspend key parts of its nuclear programme.

"In fact, Iran continues taking actions in direct contravention of its obligations to expand and deepen these prohibited programmes," Macmanus told the closed-door quarterly gathering in Vienna.

These include uranium enrichment, a process that lies at the heart of the international community's worries about Iran's activities since it could provide Tehran with material for the fissile core of a nuclear weapon.

"With a new president in office, and a new government in place under his leadership, Iran today has an opportunity to change its path from intransigence to cooperation, from obfuscation to transparency," Macmanus said, according to the text of his remarks.

Lithuania's IAEA representative said in a statement on behalf of the European Union that the IAEA's latest regular report on Iran last month that showed a continued expansion "further aggravates our deep concerns".

Edvilas Raudonikis said the EU wanted a "comprehensive, negotiated, long-term settlement, which would build international confidence in the exclusively peaceful nature of the Iranian nuclear programme, while respecting Iran's legitimate rights to the peaceful uses of nuclear energy".

Hassan Rowhani's election in June as Iranian president, replacing hardliner Mahmoud Ahmadinejad, has created some hope of a diplomatic solution to the deadlock after a decade of trying.

Rowhani has given responsibility for upcoming talks with world powers to the foreign ministry under US-educated moderate Mohammad Javad Zarif and has appointed Reza Najafi to the IAEA, replacing the long-serving Ali Asghar Soltanieh.

Zarif said on Wednesday that Tehran was pursuing a "win-win game" in negotiations while stressing that pressure would not lead to results.

"No side (in the) negotiations can conclude talks in its favour by exerting pressure," Zarif told reporters, quoted by the English-language Press TV website.

Iran denies seeking or ever having sought nuclear weapons and argues that the six UN Security Council resolutions passed against it since 2006 -- four with sanctions attached -- are illegal.