A new report by the aid agency Caritas details a marked reduction in Pacific Islanders' access to nutritious food and safe drinking water over the past year.
The agency said people across the region had suffered from an extended drought and a devastating cyclone as well as sea level rise and the overuse of natural resources.
Caritas said most of those affected were indigenous people, isolated rural communities, women and children.
The Director of Caritas Aotearoa New Zealand Julianne Hickey said the lack of adequate and nutritious food and safe water had impacted people's health and children's access to education.
"We heard of hunger, we heard of people who died as a result of that, of the hunger and the droughts and so our assessment particularly around food and water has increased to severe," she said.
Ms Hickey said there needed to be a rethink of climate aid to help the Oceania region deal with climate change and environmental impacts.
She called for donor governments to rethink their approach in light of the severe food and water shortages.
Ms Hickey said the Australian and New Zealand governments had not made climate finance additional to other overseas development funding, which still fell short of international commitments.
"There are far too many communities who are needing to either move now or to adapt urgently their way of life and their lifestyles and no climate finance is reaching them so we call for governments to urgently assess how they can ensure that funding can get to those communities," she said.
Caritas' report "Hungry for Justice, Thirsty for Change" said New Zealand continues to overemphasise "maintaining infrastructure and business as usual", while Australia's aid programme lacks a dedicated climate strategy.