Crocodile sightings in floodwaters have been claimed after heavy rainfall lashed a region on cyclone watch, with no relief in sight.
North Queensland has been hit by torrential rain for days causing road closures and multiple rescues, with three tropical lows looming off the coast.
The low pressure system off Cairns is unlikely to develop into a cyclone but has brought a deluge to the north tropical coast, with seven-day rainfall totals of up to 700mm in some areas.
Another low in the Gulf of Carpentaria was set to weaken but a system in the Coral Sea near Vanuatu could develop into a cyclone from Sunday.
The low off Cairns has been the focus for Queensland authorities with a wet weekend ahead.
Rainfall up to 300mm has been forecast between Cairns and Mackay - an area spanning 700km.
Areas such as Townsville are already drenched with a string of social media posts claiming to have spotted crocodiles swimming in floodwaters.
Multiple swiftwater rescue firefighters sprang into action when a person was reported missing in floodwaters in Townsville's Hyde Park on Friday afternoon, but they were found safe 40 minutes later having "self-extricated from the water", said Queensland Fire and Rescue.
The Bruce Highway - Queensland's major arterial road - was closed on Friday north of Bowen after severe flash flooding.
"We've had a hell of a lot of rain the last 24 hours. It seems to be sort of in different areas at different times," Whitsunday Regional Council Mayor Ry Collins told AAP.
"It's not an unexpected issue but one that still causes some headaches for any one on the highway."
Emergency services reinforcements have been sent north in preparation amid fears the deluge will cause "life threatening" flash flooding.
"We may in fact see intense rainfall across parts of this coastline over the next few days particularly between Innisfail and Ayr," the Bureau of Meteorology's Miriam Bradbury said.
"It could lead to life threatening flash flooding. Now that's more than just water moving over roads and footpaths possibly coming into your home.
"That is flooding that occurs very quickly and can pose a sudden and significant risk to your life."
On Friday evening an emergency flood alert was issued for Townsville by the local disaster management group, saying localised flooding was happening and people should be prepared to leave as conditions could change quickly.
Minor flood warnings were in place for the Mulgrave, Tully, Murray and Don Rivers with flood watches extending across the north tropical coast.
Riverine flooding impacts are set to continue into next week, the bureau said.
Almost 40 police officers have been sent north from Brisbane with rescue boats positioned from Townsville to Cairns and about 300 power company staff on standby.
The Australian Defence Force has also been briefed as authorities brace for more wet weather.
"My message to Queensland is: we are well and truly prepared - we are asking you to do the same," Premier David Crisafulli said.
