A woman has died after her car got caught in a floodway in the Northern Territory.

A police helicopter spotted the vehicle in floodwaters about four kilometres from the remote Beswick community, east of Katherine, on Sunday night.

It’s believed the elderly woman was one of five people in the car.

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“This is the second person who has been washed away in a flooded creek since Christmas,” NT Police, Fire and Emergency Commander Bruce Porter said.

“Again I urge people to avoid taking unnecessary risks on the roads and avoid driving into floodways.”

The hopes of rescuers are fading in the search for a 28-year-old man missing from Peppimenarti in the Daly River region since Christmas Day.

Rescuers say the water is too high and moving too fast to allow boat searches but helicopters are still sweeping the area.

Severe thunderstorms, heavy rain and winds are forecast for areas including Katherine as a tropical low pressure system moves across the state towards Queensland.

An earlier cyclone watch in the Gulf of Carpentaria has been cancelled but the threat remains, experts say.

Several NT communities are already underwater after the Daly River reached major flood levels.

Almost 470 people have been evacuated by helicopter from the remote Nauiyu community since an evacuation order was issued on Boxing Day.

They have been transported more than 150km away to Batchelor where an evacuation centre has been established.

The Bureau of Meteorology has issued a severe weather warning for the Daly, Tiwi, Arnhem, Carpentaria, Gregory, Barkly and Simpson areas with fears of flash flooding.

Abnormally high tides and heavy surf are forecast for coastal areas.

Residents in affected areas are warned to take precautions.

“Create your own sandbags if there is flooding by using pillow cases or shopping bags filled with sand and place them around doorways to protect your home,” the latest BOM warning advises.

Emergency kits should also be ready with a battery-operated radio, torch, spare batteries and first aid kits.

The NT Police, Fire and Emergency Services has advised motorists to take extra precautions.

“I continue to urge everyone to exercise extreme caution on the roads and to consider the necessity of their travel plans,” Commander Porter said.

“The last thing we want is for anyone to become an unnecessary statistic.”

The tropical low is forecast to cross the border into Queensland overnight.

A minor flood warning for the Katherine River at Gorge Road has been cancelled.

-AAP