Helen Clark told AFP in an interview that she had yet to decide on whether to enter the race to be the next UN secretary-general and succeed Ban Ki-moon, who steps down in 10 months.
"Every country, every major organization like the UN should expect in the fullness of time to have a woman leader," Clark said.
"But it's still too rare a thing around the world. So for sure, the UN's day will come."
The challenge for UN development experts is to help countries "build resilience" so they can confront turbulent eco-systems and extreme weather, she said.
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Development aid from the world's big donors totalled USD 135.2 billion in 2014, but some of those funds have since been diverted in Europe to refugee resettlement or fallen victim to austerity cuts.
"The countries that are not in severe conflict do worry about how much is left for development after all the major needs of the conflict crises are met," said Clark, 65, who served as prime minister from 1999 to 2008.
The meeting attended by some 80 ministers will seek to build on a summit in September during which the United Nations agreed on a new set of global goals to end poverty by 2030.
But Clark said she hadn't "offered an opinion" on whether to present her candidacy and sidestepped questions about her being naturally considered for the job as the UN's number three.
"I think there would be a difference," she said of a woman in the top job.