Widespread hunger and thirst exist across the Pacific, according to international aid and development agency Caritas, which describes the situation as severe.

It cites cases of children eating cassava roots softened with paracetamol and people dying from lack of food and clean water.

The examples are contained in the latest Caritas State of the Environment Report for Oceania, which is being launched in Parliament on Tuesday.

The report says the region's basic food and water supplies have been hit by a strong El Nino weather pattern, which has compounded the effects of cyclones Pam and Winston and ongoing climate change.

At the peak of the drought in summer, more than 4.7 million people in the region were affected by food and water issues, it says, quoting United Nations figures.

Caritas Aotearoa New Zealand Director Julianne Hickey says the impact continues to be felt, especially on health, education and livelihoods.

She says this is the reason Caritas has lifted its assessment of the state of safe food and water supplies in Oceania to severe, from high in 2015.

"According to our partners across the region, this was the most severe El Nino drought their people had ever experienced," she said.

"We heard of people walking days to get food and water in Papua New Guinea, with many becoming sick and some people dying from lack of food and access to safe drinking water."

Mrs Hickey said the report acknowledged that the Paris Agreement negotiated last December signalled an unprecedented international commitment to climate change action.

However, that now needed to be backed up with concrete action and special consideration given to the needs of the most vulnerable in the region.