Baby Neve joined the Prime Minister at the United Nations in New York on Tuesday, as Jacinda Ardern gave her first speech to the General Assembly.
"It was a very practical decision. Neve is actually nearby me most of the time in New Zealand, she's just not always caught.
"But here when she's awake we try and keep her with me so obviously that was the occasion," Ms Ardern said.
Ms Ardern spoke at the Nelson Mandela Peace Summit in the United Nations General Assembly hall on Monday morning (local time).
Ms Ardern's partner Clarke Gayford and three-month-old Neve joined her, as she spoke about Nelson Mandela's "profound impact" on New Zealand.
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"His struggle against apartheid was supported in New Zealand through a mass protest movement that opposed sporting contact between our countries, culminating in major protest events in 1981," she said, referring to the Springbok Tour protests.
She said he later referred to news of the protests being "like the sun coming out".
"Mandela was a living embodiment of the United Nations' values. It is these values and Mandela's moral example that we must look to promote in a world that is more fragmented and fractured than ever before. It's an example that calls for justice, peace and forgiveness," she said.
"Above all else, Madiba [Mandela's clan name] taught us that no issue in the world, whether it be racial inequity or indifference is insurmountable. That none of us are too small, or too far away to be relevant in the collective struggle for justice. As we remember Madiba, my hope is that we all give reason for the sun to come out."
Ms Ardern also appeared as a guest on The Today Show, gave the keynote speech at the opening of UN Climate Week, and had bilateral talks with Austria, Ireland and Columbia.
It's baby Neve's first international trip, after she was unable to join Ms Ardern on her recent trip to Nauru.
Later this week Ms Ardern will deliver New Zealand's national statement to the UN.