The Asian tsunami relief effort was hampered by rivalries between agencies, according to the British Red Cross.
The relief charity said there was no effective co-ordination and the wrong type of aid was sent.
In a report into the aid response, the Red Cross said the 2004 Boxing Day disaster initially overwhelmed agencies.
But lives were not lost as they grappled to come to terms with the scale of the tragedy.
Matthias Schmale, the organisation's international director, said: "This needs to be understood - we saw this with Hurricane Katrina - chaos breaks out by definition.
"In Sri Lanka there were 300-400 agencies responding and trying to provide help, we have to acknowledge that's difficult to manage. Effective co-ordination did not happen," he added.
"Did it lead to people being disaffected with the response? The result is yes."
Around 250,000 people were killed when the giant wave swept across south Asia, triggered by an earthquake off the Indonesian island of Sumatra.
The report, World Disasters, says some of the aid effort ignored the needs of women in some areas, Sky news reports.
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