Egypt's controversial candidate to head culture body UNESCO again failed to win the required backing on Saturday, a spokesman said, after a third vote in a process tainted by charges of anti-Semitism.

The balloting will now go to a fourth round on Monday, the spokesman said, after the the frontrunner, Egyptian culture minister Faruq Hosni, failed to win the nomination in the third round ballot of world envoys.

Envoys at UNESCO's 58-nation executive council started voting Thursday for a successor to Japan's Koichiro Matsuura as director general, with Hosni, Egypt's culture minister for 22 years, seen as the favourite.

Supporters say the Egyptian's election would send a positive signal from the West to the Muslim world, but the race has been clouded by charges that anti-Israel comments made last year make him unfit for the role.

On Saturday Hosni secured 25 votes, two more than on Friday, but still short of the 30 needed to win election, even after four candidates dropped out following the second round, according to a diplomat at the organisation.

Also in the race are Bulgarian ex-foreign minister Irina Bokova, who won 13 votes, against eight on Friday, European Commissioner for External Relations Benita Ferrero-Waldner with 11, up from nine, and Ecuador's Ivonne Baki, who improved her score by one to eight.

Ferrero-Waldner, who came in third on Saturday, was not yet pulling out, a source in her entourage said.

"Mrs Ferrero-Waldner is not quitting. We are currently analysing the results of the vote. We have not yet decided on the way forward," the source said.

The Egyptian, 71, is seeking to become the first representative from the Arab world to head the UN agency which is mandated to promote global understanding through culture, education and science.

His detractors include Auschwitz survivor and Nobel laureate Elie Wiesel, who says Hosni's appointment would "shame" the global community, as well as the Nazi-hunting Simon Wiesenthal Centre and US and French intellectuals.

In his long career, Hosni has often been accused of promoting anti-Semitism, in particular when he told the Egyptian parliament in May last year: "I'd burn Israeli books myself if I found any in libraries in Egypt."

European delegates have been negotiating among themselves to try to come up with a single candidate against Hosni.

Lithuania's Ina Marciulionyte dropped out before Saturday's vote, along with Russia's Alexander Iakovenko and two Africans, Sospeter Mwijarubi Muhongo of Tanzania and Noureini Tidjani-Serpos of Benin.

The appointment is to be endorsed in October by the 193-member assembly of UNESCO.