Calls for help will 'climb into thousands'

Emergency authorities expect thousands of calls for help as north Queensland communities realise the full scale of the damage done by Cyclone Debbie.

Authorities in cyclone-hit Queensland expect calls for help to rapidly climb into the thousands. (AAP)

Authorities in cyclone-battered north Queensland are dealing with 600 requests for help but expect that to rapidly climb into the thousands.

Queensland Fire and Emergency Services Deputy Commissioner Mike Wassing says there is significant structural damage in Airlie Beach and Proserpine, which bore the brunt of category 4 Cyclone Debbie's 260km/h winds on Tuesday.

Properties have also been damaged in the inland town of Collinsville, where Debbie swept past as a category 2.

Debbie is now a rain depression that will almost certainly cause flooding, including in the southeast corner and Brisbane on Thursday and Friday, Mr Wassing said on Wednesday.