Residents in the Northern Territory town of Katherine are on alert after heavy rain pushed a local river to its highest level in four years.
More than 250mm of rain fell in the Katherine River catchment over the past three days, the Bureau of Meteorology reported.
It peaked at 15.65 metres early on Sunday, just 35cm below the town's minor flood level.
The bureau issued a minor flood warning for the Katherine River about 9am.
"Further rainfall is possible in the area during the next few days which may affect river levels," it warned.
The river is expected to remain below the minor flood level of 16 metres throughout Sunday.
Flooding is occurring along the Katherine River Gorge Road at Nitmiluk Visitor Centre, about 30km northeast of the town, where the river is 1.63 metres above the minor flood level and is not expected to fall over the next two days.
It is also rising at Birdie Creek about 80km northeast of Katherine, which is 320km south of Darwin.
NT Police have urged residents to take care.
"Don't go into flooded waterways and don't launch watercraft into swollen rivers," Commander Janelle Tonkin said.
"The unseen hazards under floodwaters could result in serious consequences."
Katherine famously flooded in 1998 when Cyclone Les dumped heavy rain across the Top End.
Some residents were stranded on rooftops as the Katherine River reached 20.4 metres on Australia Day that year, prompting the evacuation of about 5000 people.