The top climate change adviser for the United Nations has been nominated to head the UN Framework Convention on Climate Change (UNFCCC), a UN spokesperson confirmed on Thursday.

Hungarian Janos Pasztor, who advises UN Secretary-general Ban Ki-moon on climate change, has been nominated by Hungary's president for the candidacy of executive secretary of the UNFCCC, said spokesperson Martin Nesirky.

It is uncustomary for the UN to reveal the names of candidates for the world body's open positions, but because Pasztor works closely with the UNFCCC, which raises suspicions of a conflict of interest, an exception was made, Nesirky said.

"Although we do not normally comment on the names of candidates we understand the interest on the candidate who works for the secretariat," he told reporters. "Upon the announcement of his candidacy, Mr. Pasztor was asked to disassociate himself from activities relating to the UNFCCC with immediate effect."

Eleven candidates from 11 different countries are competing to replace Yvo de Boer, who will be stepping down on July 1.

"The appointment will be made following a normal competitive process run by a selection committee with a bureau of the UNFCCC," said Nesirky. "All candidates will go through the same process."