A river has burst its banks and begun flooding an outback town after the entire community was evacuated to safety.
More than 400 people from Daly River were bussed 230km to Darwin or made their own way out on Wednesday.
Bureau of Meteorology NT manager Shenagh Gamble told reporters in Darwin on Friday the river had overflowed its banks and was starting to inundate the town.
A huge volume of water was flowing down the river at the rate of about three tonnes of water per second, she said.
The river was at 13.3 metres on Friday afternoon but was expected to rise to a major flood level of 14m, peaking on Monday or Tuesday.
Ms Gamble said it could be some time before residents were able to safely return to Daly River.
Incident controller Superintendent David Moore said 298 evacuees, including 110 children, were housed at the Foskey Pavilion at the Darwin Showgrounds.
He said assessment teams would go in and check facilities were safe and operable as the flood waters receded before evacuees could return.
That included checking roads, water, electricity supply and the sewerage system and assessing whether individual homes were safe.
"It's safer to be in Darwin until we can give the all-clear that it's safe to return," Supt Moore told reporters on Friday.
He said he had no reports of homes being inundated but the waters were rising, particularly on the northern side of the town, and the airport was largely underwater.
The evacuees have expressed concern about having to start all over again if their homes are inundated and are worried pet dogs left behind could be taken by crocodiles.
Supt Moore said an animal welfare officer was at Daly River, along with police, watching out for the dogs left behind and supplying them with food and water.
Off the West Australian coast, meanwhile, a tropical low to the west of Broome is forecast to develop into a tropical cyclone by Saturday morning.
The Bureau of Meteorology said the system would continue to move in a general west-southwest direction across the weekend, tracking towards the Pilbara Coast.
"It should continue to develop and is likely to reach category two intensity by Saturday evening," the bureau said on Friday.
The system could turn in a more southwesterly direction on Sunday and impact the western Pilbara.
