The decision by Vanuatu's president and senior disaster officials to fly to a conference in Japan as Cyclone Pam bore down on the Pacific nation in March made response efforts more difficult, aid group Save the Children says.
As the category five cyclone approached Vanuatu, President Baldwin Lonsdale and the director of the National Disaster Management Office Shadrack Welegtabit left for Japan.
"It meant that you had someone in a very senior position that was playing a key role in coordinating the international response that didn't have the experience of the person who normally would have been in that position," Save the Children Australia's Rebecca Barber told the ABC.
Cyclone Pam killed 11 people when it struck on March 13 and left hundreds of thousands of others in need of food, water and shelter.
A report by four major international aid groups in Vanuatu on the lessons learnt from the disaster — titled One Size Doesn't Fit All — found tensions between foreign experts and the national government undermined the response.
It said some international organisations bypassed Vanuatu's planning and lacked cultural awareness, culminating in a government official threatening to arrest those who distributed aid without permission.
"That highlights the issues created by the vast number of NGOs coming in, not all of them coordinating," Barber said.
Aid agencies described the cyclone as one of the worst disasters to ever hit the Pacific region.
But in many ways Vanuatu's preparation for, and response to, the category five system was seen as a success story, with the relatively low death toll.
The report said one of the positive lessons learnt was the value of community disaster committees, which helped to reinforce houses, stockpile food and water and survey the damage after the cyclone.