Much of the aid sent is food or clothing from well meaning, generous people, but if it is unsolicited it can end up sitting on wharves, deteriorating, and then having to be thrown away.
As another cyclone seasons begins in the Pacific the World Food Programme is calling on people to donate responsibly.
The director of the WFP in the Pacific, Jo Pilgrim, said this unsolicited aid, arriving by the container load, or in cartons, can be food stuffs, water, clothing, household items and so on.
But it is typically not what is needed in the middle of a disaster, and she gave the example of what happened in Port Vila in Vanuatu at the height of Cyclone Pam in 2015.
"And once accessed half the food items were expired and had to be disposed of, but the total cost of storage, handling and container rental fees to the government of Vanuatu was 2.5 million dollars," she said.
"Now two and a half million dollars is a lot of money to be able to spend on things that you actually need, rather than disposing of things that the generous public sent, thinking it was going to be helpful and it wasn't," Ms Pilgrim said.
The humanitarian director for New Zealand's Council for International Development, Aaron Davy, said that astonishing items were sent to Port Vila during Pam.
"There was the shipping container sent of just left sided shoes, and stuff like that, so quite often it is things people are trying to get rid of - skis, chandeliers, lots of inncredibl stuff gets sent over," Mr Davy said.
Jo Pilgrim said cash is by far the most effective response, "It doesn't need to wait for delivery. As we know cash can travel the world instantly. It allows first responders to buy exactly what is needed, on the ground, and determine the priorities as they go. It's flexible so if priorities change you can change what you use the money for. And investing in local goods and services and businesses keeps people in jobs and helps the local economy recover faster."
In Tonga the experience is a little different.
Our correspondent in Nuku'alofa, Kalafi Moala, said Tongans living overseas are wary about sending money home to families during disasters, fearing it will be misspent - go to churches, for instance, instead of to provide food or shelter for the family.
He said one successful activiity that has taken place has Tongans in New Zealand paying for food items in this country, then a company in Tonga is contracted to deliver those items.
"And they are appropriate food item. They are not like boxes of cereals or other stuff that Tongans don't eat. And so they will deliver chicken, or any kind of meat, they will deliver vegetables and all those kinds of things. You pay cash in New Zealand and a company, locally, will do that," Mr Moala said.
The WFP said its Donate Responsibly website shows generous donors know what is appropriate and what isn't in terms of aid, with the aim of getting the most effective aid to those who need it.