The Pacific is the only region in the world where undernourishment has increased in the past 12 years.
The new United Nations research said climate change is a key driver in a rise in world hunger.
Oxfam New Zealand's Angela Wilton said this is especially true for the Pacific, where 7 percent of the population is undernourished.
"The Pacific certainly came out with very strong statistics, indicating this paradox of both obesity, but also nutritional deficiencies leading to wasting and stunting," said Angela Wilton.
In Papua New Guinea, 50 percent of children are stunted by malnutrition, and nearly 20 percent of adults are obese, the UN Food and Agriculture Organisation's State of Food Security and Nutrition in the World report found.
Notably, the driver behind a regional increase in undernourishment appears to be New Caledonia, where rates jumped from 8 percent to 12 percent.
In Fiji, the Solomon Islands, Vanuatu and Kiribati, undernourishment was down slightly.
Earlier this month, the Pacific Islands Forum stated formally that climate change represented the "single greatest threat to the livelihoods, security and wellbeing of the peoples of the Pacific.
"A recognition of the severity of this issue is significant. So, for climate change to be identified in this way goes a long way," said Ms Wilton.
But climate change has been consistently mislabelled as an exclusively environmental issue, said Ms Wilton, when it needed to be treated as a human rights issue as well.
"Be they tropical storms or droughts or natural disasters etc., it is leading to an increase in people being hungry around the world."