Dozens of prisoners have been released from jail in Papua New Guinea to forage for food after two months of severe shortages led the authorities to take “desperate” measures.

All except one of the 35 inmates returned to Boram prison in Wewak, East Sepik after gathering food. The jail holds 290 men, most awaiting their day in court.

Prisons manager Joe Imini told the National newspaper that shortages had occurred because the government in Port Moresby were slow in releasing funds to pay for monthly rations. This forced officers and their families to make up the food shortfall, a situation Imini described as unsustainable.

The prison usually receives $18,000 a month to feed its inmates, but in April this figure was decreased to $7,000, leading to severe shortages. The “desperate” solution, Imini said, was to release some of the prisoners to collect food outside the walls.

“Given the size of our population, that [$7,000] is not enough. Payment is not forthcoming. We are living on credit,” Imini said. “Pressure is mounting. They were hungry. So we chose 35 of them to go out. All but one came back.”

According to the World Health Organization, malnutrition is common in the country. Unicef has described it as “a silent emergency” and the underlying cause for the majority of deaths in children aged under five.

Unicef reported that malnutrition had become multi-generational in PNG, and made children and adults more susceptible to dying from treatable diseases such as diarrhoea and chest infections.

A 2017 report by Save the Children and Frontier Economics found malnutrition could be costing the country $1.5bn a year, representing 8.45% of its gross domestic product.

Save the Children’s head of policy, Majella Hurney, said Australia – PNG’s largest bilateral donor – directed only 0.1% of its aid funding toward nutrition programmes, and this should be increased.

“Our report shows that nutrition interventions have comparatively high economic and social returns on investment,” said Hurney. “It is critical to invest in human development as a foundation for inclusive and sustainable economic development. Otherwise, malnutrition will continue to undermine the great human and economic potential of our nearest neighbour.”