The Australian Navy has cleared the shipping channel of debris along the coast of Queensland from Caloundra through Moreton Bay to the Port of Brisbane.
Debris has been flowing down the Brisbane River since major flooding last week.
Pontoons, trees, wrecked boats and even a restaurant were all washed downstream.
HMAS Huon has been sweeping the channel since Tuesday.
Lieutenant Commander John Relyea said other parts of Moreton Bay would be searched next. The ABC reports that two survey boats will join HMAS Huon in the work.
"The sonar can see through the cloudy water and later on, if it's clear, we can put divers in the water or use the double eagle submersibles to visually identify," he said.
"It's got a camera on board and also a sonar so it can actually see objects."
Lieutenant Commander Relyea said more debris is expected as they continue searching.
"Thankfully so far we haven't seen a lot, even from Caloundra in the channels, they are pretty much as they were beforehand," he said.
"There's not a lot of debris up there, there are no significant obstructions so far, but we expect that will change as we get further towards Redcliffe and (Moreton) Bay but so far so good."