An advisory group on American Samoa's coral reefs says anecdotal reports on the impact of last week's tusnami show extensive structural damage in some areas.
The Coral Reef Initiative's co-ordinator, Jeremy Goldberg, says teams of divers have been inspecting the reefs and he expects to be able to issue a report on their condition within the next couple of days.
He says the territory's renowned for having some of the Pacific's most pristine and resilient coral, with five times as many species as Hawaii.
Mr Goldberg says clearing the reefs of debris quickly is crucial to prevent it from causing more damage as it's moved by wave action.
"Some of the anecdotal evidence coming in is that there has been a tremendous amount of structural damage done to a few of the coral reefs around some of the heavily impacted areas. Large amounts of debris have been seen on some of the reefs. But it's looking like the damage is moderate in most places and even minimal in some habitats so that's a good sign."
Jeremy Goldberg of American Samoa's Coral Reef Initiative.