Don't expect a public endorsement for Helen Clark from the US, even if they decide to vote for her.

US Vice President Joe Biden yesterday gave a strong hint they're considering voting for her, in the race to become UN Secretary General.

Mr Biden said he was impressed at the bipartisan support being offered to Helen Clark for the top UN job by John Key.

He said the American administration held Miss Clark in very high regard.

But Labour MP and former UN worker David Shearer said that's probably all the US will say on the matter, and they certainly won't endorse Ms Clark.

"Basically it can often backfire, and be the kiss of death, because other countries might vote the other way."

However, the fact that the USA is considering Clark is being taken as a win.

Shearer believes this at least means there's one less veto to worry about.

"If one of the permanent five members vetoes a candidate, that means the candidate is effectively out."

The permanent members of the UN Security Council that hold a veto are the USA, Britain, France, Russia and China.