Firstly, unsolicited goods take far more time, effort and cost to reach their destination than a cash contribution does. Containers of goods need to be transported, cleared by customs, sorted and distributed by a team on the ground. This can end up costing aid agencies money that could be used much more effectively in helping those in need.
If food, clothing and medical supplies are needed, certain organisations are geared up to provide bulk supplies quickly, without having to divert members of their team to sort through incoming donated items.
Secondly, local economic activity is crucial to restoring livelihoods after a disaster. Free goods shipped in from New Zealand can distort local economies by forcing down the price of locally produced items, and compete with local retailers, making it more difficult for locals to get back on their feet.
Instead, cash donations can be used to support the local economy through aid organisations buying items locally, or increasingly through cash transfers to affected households that purchase what they need most in local markets. This helps to stimulate the economy and provide for immediate needs quickly and effectively following a crisis.
Thirdly, unsolicited goods are often not appropriate. Sending heavy winter clothing to Pacific Islands (this actually happens) will not really benefit those in need, and toys are secondary in need to clean water, food, shelter and the rebuilding of livelihoods.
These non-life-saving items can clog up docks and airports and prevent lifesaving supplies from reaching disaster-affected areas.
A cash donation to an appeal helps aid agencies to buy whatever is needed quickly to meet the changing and complex demands of affected communities.
The final point to consider is culture. In places with a strong culture of gift-giving, people may not refuse unwanted goods for fear of seeming impolite or ungrateful. Think of those well-meaning gifts you received at Christmas that you politely accepted but remain unused, taking up storage space. This often occurs in disaster-affected countries but on a much larger scale and with more detrimental consequences.
Not sending goods doesn't mean you can't help. If you have unused items around the house, try selling them in New Zealand to raise money to give to a registered charity who has launched an appeal.
Experts predict that we are likely to see an increasing intensity of cyclones this season (officially November to April) in the Pacific. Experience tells us that the best way to help our island neighbours is to donate to a reputable aid agency and make sure that your cash donation reaches those who need it most.
Ian McInnes is chairman of the NGO disaster relief forum which represents 16 of New Zealand's international aid and development organisations.