Emergency crews have conducted three rescues in the Northern Territory after motorists attempted to cross causeways flooded by heavy rains.

Key points: Two people rescued by helicopter at Borroloola

Two people rescued by helicopter at Borroloola Three cars swept off roads by floodwaters

Three cars swept off roads by floodwaters Vigorous monsoonal conditions continue across Top End

At 6:00am on Saturday a number of people were rescued from a four-wheel drive ute towing a boat which was swept off the Arnhem Highway at Marrakai, 100 kilometres south-east of Darwin.

A second car swept off the Arnhem Highway at Marrakai was also inundated by floodwaters but the occupants were able to free themselves.

While two other vehicles in nearby locations became stranded when the motorists attempted to drive through flooded roadways.

Police said one rescue involved a helicopter supplied by the nearby McArthur River Mine.

A car towing a boat stuck in floodwaters at Wyatt Creek of the Arnhem Highway. ( ABC News: Terry McDonald )

"The helicopter rescue was near Borroloola, near the Heartbreak Hotel, and police couldn't actually get to that particular incident and we were assisted by the McArthur River Mine in using a helicopter to rescue two people," acting Assistant Commissioner Matthew Hollamby said.

"Nobody's been hurt, but obviously spending a number of hours on top of your car isn't pleasant."

With more heavy rain forecast, police are urging motorists not to drive on roads which have been closed, and to take precautions when driving off main arterial roads.

A crocodile rides the waves at the mouth of Rapid Creek in Darwin. ( Supplied: Andreas Heikaus )

January rainfall average exceeded

The Bureau of Meteorology issued a severe weather warning for damaging winds and heavy rainfall for people in the Daly, Gregory and parts of the Carpentaria, Barkley and Tanami districts.

It warned vigorous monsoonal conditions were expected to bring floods to the western Top End this long weekend and early next week, with widespread daily rainfalls of 40-60 millimetres forecast and isolated totals of 100mm.

The wild weather triggered a warning for damaging surf in parts of the Daly and Tiwi districts, with the conditions bringing rarely-seen waves to Darwin beaches.

The wild weather has brought a big swell to Darwin's beaches. ( Supplied: Andreas Heikaus )

In the 24 hours to 9:00 am on Saturday, widespread falls of 50-100mm happened across the Greater Darwin area, with 99mm recorded at Darwin Airport, 119mm at Noonamah and 113mm at McMinns Lagoon.

Darwin exceeded its January average rainfall of 424mm, having reached 496mm as of 9:00 am.

There were strong wind gusts of up to 89 kilometres per hour at Darwin Harbour and 74 kph at Darwin Airport.

Wind gusts reached 89 kph in Darwin and brought trees down. ( Facebook: Darwin parkrun )

Daly River residents urged to be vigilant

Meanwhile, the BOM revised down its predictions for waters to rise in the Daly River community, following an evacuation order that was cancelled on Friday.

"Northern Region Emergency Committee teams — including those at Foskey Pavilion — remain on stand-by, however at this stage there is no need for the evacuation of the Daly River community," acting Assistant Commissioner Hollamby said.

"The Daly River Emergency Plan is still active and residents are urged to remain vigilant."

A fallen tree outside Parliament House in Darwin. ( ABC News: Alan Dowler )

NT Police said Telstra was working to restore communications in Daly River and a number of other communities including Wadeye, Peppimenarti and Nganmarriyanga.

Mobile phones, landlines and ATMs were affected.

"Telstra is aware of the issues and is working to restore services, with technicians heading to the area [on Saturday]," Assistant Commissioner Hollamby said.

Motorists should monitor Road Report NT and BOM information before travelling on the road in wet weather, police said.