Race for top job at UN: How does it work?

Analysis: The race for the job of head of the United Nations is heating up overnight. Kim Griggs explains how the world's weirdest job selection for the world's top diplomatic job works.

What happens tonight?

It's complicated. Today's vote is the first on coloured paper. And yes, that is significant.

The so-called P5, or the permanent members of the Security Council - the US, Russia, UK, France and China - will vote on red ballots indicating they have the power to veto the choice. The other 10 members, (the Elected 10), get white paper. Each member of the Security Council votes for each candidate: encourage, discourage, no view.

In the last poll Helen Clark got six 'encourage' votes, nine 'discourage" and no 'no opinion'.

Tonight's vote, like all the rest, is meant to be confidential but that's in the 'yeah, right' category. The results of every poll so far have been posted to Twitter almost immediately.

So what happens if you get a veto in today's poll?

Nothing straight away. All that it means is that the candidate will know that one of the P5 - who have the power to veto any candidate's selection - doesn't think they're up to the job. But since tonight's poll is still informal, it's not yet an actual veto.

But if you get a veto in this vote will you be eliminated? Like on Survivor?

Not necessarily. The only vote that actually counts is the final one, so hanging in there and continuing to lobby - as Helen Clark is doing - is an option. And the Security Council doesn't eliminate candidates; it is up to individuals to withdraw.

So why bother with the coloured ballot papers then?

Our UN correspondent, Lorna Shaddick, says last time round, when Ban Ki Moon was chosen, it was considered the best way of winnowing down the field of candidates. She says once it's clear one of the permanent members - they are the US, Russia, UK, France and China - might block you, it's probably not worth carrying on.

But the colour-coded ballots are controversial. The elected members have said they'd prefer not to have them at all. That way the permanent members would have the same influence throughout the straw poll process.

So who is still in the running?

#Helen4SG, of course. And it seems like she's here for the duration. She told Forbes in an article published just yesterday: "You just have to hang in as an option because [of] the way geopolitics are."

There are four other women still in contention for the job - including a Bulgarian candidate who has just entered the race - and five men. But what's different this time is that after 70 years of blokes in charge of the UN, there's been explicit encouragement for women to put their hands up for the top job. Even with that call from the President of the United Nations and the incumbent Secretary-General Ban Ki Moon, it's Portugal's former prime minister Antonio Guterres who is, so far, the preferred candidate.

How's Helen doing?

Helen Clark is sitting seventh after the first five informal polls But the addition of the Bulgarian candidate, Kristalina Georgieva, isn't good news. In geopolitical terms, it's Eastern Europe's turn. So Kristalina Georgieva is both a woman AND from Eastern Europe AND Bulgaria's European commissioner. Mark Leon Goldberg, who edits the global affairs blog UN Dispatch, has told RNZ the new Bulgarian candidate is bad news for Miss Clark. "Her chances before Kristalina Georgieva's entrance into the race were quite low, and now they've gone from low to virtually nil."

So when is this poll with the coloured papers?

The vote is expected to be take place at 10am Wednesday in New York. So that's 3am Thursday here. The results should be known early tomorrow morning.

When will the final vote that chooses the candidate be?

Hopefully by the end of the month. But there's no schedule for the voting. But once the Security Council has taken its final, formal, vote, it then makes its recommendation to the United Nations General Assembly.

But just to make things even more complex, if the Security Council can't decide on one candidate, they can put two or even more names forward to the UN General Assembly.

I told you it was complicated.