People are being warned to remain in shelter as a cyclone red alert remains for coastal and island communities from and including Kalumburu to Mitchell Plateau.

A yellow alert extends from the Mitchell Plateau to Cockatoo Island, while a blue alert is in place from Cockatoo Island Beagle Bay but not including the town of Derby.

Tropical Cyclone Marcus is expected to intensify back into a severe tropical cyclone once it passes over the water on Monday.

Wind gusts of up to 120 km/h are predicted to continue for the rest of Sunday as the tropical cyclone passes over the far north Kimberley.

These winds will become confined to coastal parts between Mitchell Plateau and Cockatoo Island and may extend as far south as Beagle Bay during Monday.

Heavy rain and flooding in low-lying areas is also likely over the next 48 hours and several roads have been closed.

The Bureau of Meteorology predicts the cyclone should move off the coast on Monday morning, but it is unlikely to move far enough south to impact Broome and Derby.

Tropical Cyclone Marcus battered Darwin on Saturday, as 130km/h winds brought down trees and power lines.

NT Chief Minister Michael Gunner said there were no reports of injuries by midday on Sunday, but added that "it feels too good to be true".

"People were prepared. They did shelter and I think we saw what nature can do," he said.

Emergency services have moved quickly onto the clean-up with weather reports suggesting monsoonal activity could hit the region during the week.

"The best thing we can do is ensure everything is secure, so that's our focus at the moment," NT Emergency Services Chief Officer Jason Collins said.

He warned people to take appropriate precautions when cleaning up around their properties, particularly steering clear of power lines.

"We cannot guarantee they will be made safe as yet. Most will be, but we cannot guarantee it at the moment," he said.

"If you see a line down or in an unusual position, treat it as live."

Power and Water Corporation has received more than 400 reports of fallen power lines, leaving 25,000 properties without power.

"We'd like to advise our customers that the extent of the damage means it could potentially take several days to fully restore services to some areas," the company wrote on Twitter.

Schools will be closed on Monday while Mr Gunner has urged businesses who can stay closed to do so. The public service will run on a skeleton staff.

"Please look after yourself, your staff and families. If you don't need to open, don't open," Mr Gunner said.

Australian Associated Press