Darwin has been battered by destructive winds reaching 205km/h, the most powerful to hit the city since deadly Cyclone Tracy, ripping off roofs and tearing a section of the city's major hospital roof apart.
Severe Tropical Cyclone Fina passed the coast as a category three overnight, with the weather system's gale-force winds leaving a path of destruction as it continues west into the ocean.
There are no reports of injuries; however, power remains out across much of the region.
Part of the roof at the Royal Darwin Hospital collapsed on Saturday, with reports there is water in the building.
Residents in Darwin and surrounds were told by emergency authorities to stay in their homes or emergency shelters until given the all-clear.
Category-three Fina brought destructive winds and heavy downpours to remote Tiwi Islands communities, then Darwin and surrounds on Saturday and into Sunday.
Severe Tropical Cyclone Fina crossed the coast near Darwin as a category three overnight.
Forecasters had Fina tracking just north of Darwin.
Northern Territory Police incident controller Kirsten Engels urged residents to stay at home, but the sweeping sheets of rain on the streets and high wind gusts kept pretty much everyone indoors anyway.
Emergency shelters were open in Darwin, nearby Palmerston and adjacent rural areas, with people urged to bring their own bedding and food.
Videos showed the cyclone's destructive power, ripping a powerline apart and causing a small explosion of sparks.
Powerful winds also brought trees down across the city.
Australian Defence Force personnel are on stand-by to help with the clean-up efforts, and financial assistance will be available to support local governments and communities as they recover.
Fina is the Northern Territory's strongest cyclone to pass Darwin since Cyclone Tracy in 1975.
Now tracking west-south-west, Fina is picking up strength over the Timor Sea and could hit the top of Western Australia in coming days.
A cyclone warning remains in place from Wadeye to Cape Hotham including Tiwi Islands, Dundee Beach, Darwin, Milikapiti, Pirlangimpi and Wurrumiyanga and a watch zone is active from Wadeye in the NT to Troughton Island and Kalumburu in WA.
According to the Bureau of Meteorology's 4.30am update, sustained winds near the centre of the cyclone reached 140 kilometres per hour this morning and Fina produced wind gusts up to 195km/h.
The Bureau said conditions are forecast to ease through Sunday, after the worst of the damaging winds lasted from about 6pm to about midnight on Saturday.
But Fina could intensify to a category four tonight, into the early hours of Monday, according to the latest cyclone track map.