"It is a decision for her to make, as to whether she wants to run.
"That is an important question, it is obviously a live question, but it's not one that I can influence."
There was a strong mood for a woman Secretary General, he said, with lobbying led by Colombia for a woman to be appointed after eight males.
However, regional politics could play a deciding hand. The Eastern European countries had made it clear it was "their turn", Mr van Bohemen said.
"All of the candidates nominated so far have come from Eastern Europe, and I think there is a general recognition that it is for them to lose.
"But they have to find a candidate that can get support within the group, and they haven't got one of those yet, because everyone is nominating their own candidate. And then they have to have support from the rest of the Security Council."
Helen Clark is already No3 in the United Nations hierarchy as head of the United Nations Development Programme.
The rules say that the general assembly makes the appointment on the recommendation of the Security Council, on which five countries have veto rights.
In about 10 months, New Zealand's two-year stint on the Security Council will end. New Zealand was last on the council in 1993-94, and had spent 10 years campaigning for a second tenure.
Mr van Bohemen told the select committee that a recent New York Times article that described 2015 as the year of "the great unravelling" was accurate.
"This sense of the unravelling world is a very big part of the Security Council picture. We are dealing with a lot of big problems that show that some of the traditional understandings of how the world is constructed have been challenged, especially in the Middle East, but also in Africa."
This had impacted the Council's own effectiveness. Relationships between permanent members was "one of the most difficult since the end of the Cold War".
That tension mostly traced back to Russia's annexation of Crimea, and continued engagements in Eastern Ukraine.However, one positive had been New Zealand's hosting the 15 members of the Security Council at a "Kiwi breakfast" during its presidency in July.
Mr van Bohemen said that took place in "an infamous New Zealand residence" - the $11 million apartment recently bought as residence for him just across the road from the UN.
The breakfast provided a chance for more meaningful dialogue between members, including on the issue of the permanent members' veto powers, than other more formal meetings that could be a "place more for political theatre than problem solving".
Since the breakfast, other countries had hosted similar breakfasts at the beginning of each month.