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.
Unprecedented water releases from the city's swollen dam have sent torrents of water down the Ross River and into the city, swamping roads, yards and homes.
Crocodiles have been spotted in suburban streets, and the water is teeming with snakes.
It's unclear how many more homes may have been inundated. On Sunday the figure was between 400 and 500.
But that was before dam releases doubled to their maximum level in anticipation of more rain, sending almost 2000 cubic metres of water per second charging out of the Ross River Dam.
Authorities have warned between 10,000 and 20,000 homes could be at risk.
With days of more rain ahead, the crisis is far from over and the premier says forecasters are closely watching the monsoon trough amid fears it could form into a cyclone if it moves off the coast.
"This system, if it moves out to the sea, it could develop into a cyclone," she told Seven Network on Monday.
"These are early days and we won't know for certain until the next few days."
The Bureau of Meteorology has also warned that tornadoes could form, with gale-force winds seen in Townsville overnight.
Queensland Fire and Rescue Services received 850 calls for flood assistance in the past 24 hours, most in Townsville.
The premier said about 200 callers were still waiting for help on Monday morning.
The weather was atrocious overnight, with two police engaged in evacuation work rescued themselves after fast-rising flood waters trapped them and washed away their patrol car.
They were rescued after spending half an hour clinging to trees.
"It was just bucketing down last night ... and the wind gusts were huge. It was a tough night," the premier said.
Water releases from the dam sparked emergency flood alerts late on Sunday, with residents in 21 Townsville suburbs told to move to safety.
The dam is expected to peak at 11am on Monday and remain at that level until at least midnight. Spillway gates remain open at their maximum level.
The premier said the dam had been managed well and the council did what it had to do.
"We've got catchments that feed into the Ross River Dam so there's even more water coming in over the next 24 to 48 hours. That water needs to go somewhere," she told the ABC.
"Townsville has never seen the likes of this."
About 1000 people have headed to evacuation centres, with one of five centres now full. The council will decide on Monday if more centres need to be opened.
Schools in Townsville remained closed on Monday along with the city's airport.
The monsoon trough that's been dumping flooding rain on north Queensland's east coast, and drought-hit parts of western Queensland, will drive the state's emergency for days to come.
Intense rain with significant flash flooding is expected between Ingham and Bowen, and possibly as far south as Mackay, extending inland to Mt Isa near the Northern Territory border.
Australian Associated Press