The U.N. Security Council voted on Monday to introduce a third sanctions resolution against Iran over its refusal to halt nuclear work that major powers fear is aimed at making bombs but which Tehran says is designed to generate electricity.

Addressing a meeting of International Atomic Energy Agency (IAEA) governors in Vienna, Pretoria's envoy Abdul Minty said the resolution's sponsors failed to take into account progress made in resolving questions about Iran's programme.

"South Africa furthermore regrets that the adoption of the new resolution could apparently not be postponed until the board had the opportunity to consider the matter ...," he said.

"This creates the impression that the verification work of the agency and the important progress that has been made is virtually irrelevant to the co-sponsors of the resolution."

It was not clear why South Africa apparently backtracked but it is a pillar of the Non-Aligned Movement (NAM) of developing states to which Iran belongs.

South Africa, one of the most influential members of NAM on the Security Council, had favoured delaying a vote to allow Iran more time to address the IAEA concerns.

Libya, Vietnam and Indonesia had also voiced reservations about the resolution, but vigorous Western lobbying managed to persuade all except Jakarta.

Tehran has ignored three previous council resolutions demanding that it freeze its uranium enrichment programme.

There were some fears within the world body, especially among NAM members, that the resolution could prompt Iran to stop cooperating altogether with the IAEA.

Iranian officials have denounced the new resolution, which includes an increase in the number of individuals and firms on a U.N. travel and asset-freeze blacklist, as illegal and made clear they would not suspend the nuclear programme.