The floods brought snakes and crocodiles onto the streets and disrupted electricity supply in the region.
The extreme rain forced officials to open the floodgates to the Ross River Dam, south of Townsville, on Monday after the water level climbed to 224 per cent of its capacity.
The floods have been declared a catastrophe by the Insurance Council of Australia, while the government is giving each displaced resident up to $130, to help cover the cost of food, medication and clothing.
Thousands of residents in the area have already been affected, some left without power and others cut off by flooded roads.
"With that we expect to see more episodes of that real intense heavy rainfall that could lead to flash flooding".
Residents in Northern Queensland are now battling once in a century monsoon weather and record rainfall, but it's not just the water that they need to be anxious about! Queensland Police also warned locals that there may be human waste in the flood water.
He said: "The volume of water is just incredible".
Emergency crews have been stretched to the limit in flood-hit Townsville, with hundreds of people still waiting for help and evacuation centres filling up fast. "It was a tough night", the premier said.
About 400 Townsville residents sought shelter at nearby Lavarack military barracks, and the Red Cross also assisted with the response and recovery effort.
That order sparked warnings that 21 suburbs could see flash flooding, including high velocity flows that could kill people.
Ms Palaszczuk warned that the communities face more difficulties ahead.More news: Heat's Dwyane Wade named to All-Star Game by Adam Silver
Some 1.3 metres (4.3 feet) of rain fell over 7 days in some areas in 1998.
TRT World's Craig Vermay reports.
The city of Townsville in North Queensland has been hit with calamitous flooding with a years' worth of rainfall coming in just nine days.
Annastacia Palaszczuk, the Premier of Queensland, said she had "never seen" floods so devastating.
"The fact that people are safe today here in Townsville I think is an extraordinary achievement and something that the people of Townsville can pat themselves on the back on", Mr Morrison said.
"(It) was almost a meter or two long (3.3 to 6.6 feet)", she said.
There has been a silver lining, with drought-stricken farmers in western Queensland welcoming the soaking.
The Queensland Bureau of Meteorology issued a major flood warning for Townsville on Sunday night, saying that "conditions will change rapidly & continuously" due to "unprecedented areas of flooding".
He warned resources "are now being stretched beyond normal with the severe weather seasons getting longer and more complex".