The International Atomic Energy Agency's board of governors decided on Wednesday to hold a vote on March 26 to choose a successor to IAEA Director-General Mohamed ElBaradei, diplomats said.

The vote by the U.N. nuclear watchdog's 35-nation governing body will pit Japan's ambassador to the agency, Yukiya Amano, against South Africa's Abdul Samad Minty, who both have long experience in non-proliferation and disarmament posts.

Amano is favoured over Minty but remains short of a 2/3 majority required for victory, according to Vienna diplomats involved in consultations.

The transition takes place at a time of a potential diplomatic opening that could aid the IAEA's efforts to stem the spread of nuclear weapons know-how.

The West has been locked in a dispute with Iran over its nuclear programme but new U.S. President Barack Obama has signalled a readiness for direct talks with the Islamic Republic.

Neither Amano nor Minty are viewed as ideal candidates who would transcend divisions between industrialized and developing nations complicating the IAEA's mission to stop proliferators and improve sharing of nuclear energy for peaceful purposes.

A senior diplomat who was in Wednesday's board meeting said there would be three rounds of secret balloting if needed to produce a winning margin. If the vote proved inconclusive, board chairman Algeria could throw open the field to new candidates.

ElBaradei plans to leave office in November after three terms spanning 12 years. The Board of Governors must choose a successor by June at the latest.