Villages in American Samoa, which suffered the most damage from the tsunami, will be the first to get an underwater assessment of their coral reefs from a team from the National Oceanic and Atmospheric Administration.
A team of 14 divers and scientists is to begin scoping the waters surrounding Amanave, Poloa, Fagasa and Leone to survey the coral reefs and remove debris.
Fagatele Bay Marine Sanctuary will also be assessed.
The village mayors have been briefed about the mission which is expected to last two weeks.
Kris McElwee, the Pacific Islands Programme co-ordinator, says a major concern is roofing iron covering sections of the reef and killing them.
"Another concern is that these large pieces of debris will be possibly moving around when the hurricane season strikes in a few months and a big concern is that any damage that's been done - there could be additional damage done when big waves come in with the hurricanes."
Kris McElwee, the Pacific Islands Programme co-ordinator