Helen Clark will face her sixth Security Council ballot early tomorrow in her bid to become UN Secretary General but it will be the first one in which the permanent five will vote with a red ballot.
It will also be the first ballot in which Bulgaria's new candidate, European Union Commissioner Kristalina Georgieva, is a candidate.
Bulgaria has pulled support for its previous candidate, Unesco chief Irina Bokova, but Bokova is staying in the contest.
Any red ballot exercised will indicate a potential veto by any of the P5 countries: the United States, China, Russia, Britain and France.
It is expected that Clark will attract at least two vetoes, one from Russia which wants an Eastern European candidate, and one from France, which also wants an Eastern European.