A reef expert says it could take decades for Hervey Bay's coral, off south-east Queensland, to recover from the most recent floods.
University of Queensland researcher Ian Butler estimates up to 80 per cent of coral has died in some regions after the January floods.
He says the impact of the floods will be severe.
Mr Butler says he expects the recovery will be similar to that which took place after the 1992 floods.
"If enough coral remains after these floods I would expect it to be the same period of time, so I'm thinking 10, 20 years - decades of time to recover to get back to where they were, if they get a chance," he said.
"If we keep getting these floods then I really don't know what to think about what's going to happen.
"I don't think the prognosis is very good for [this year].
"I have been snorkelling out on them and actually within the first week of the January floods - the corals were already dead and rotting, a lot of coral.
"In places I estimated up to 80 per cent.
"In certain places large numbers of corals are dying and through the snorkelling I've been doing I've just been seeing more and more coral dying."
© ABC 2013
14:39 EDT Residents are being warned to check the rules around this year's cyclone hazard collections.