Fifty thousand people may have to evacuate their homes in and around Sydney after eight months' worth of rain fell in four days.
Flooding has submerged roads and bridges, and left emergency services scrambling to rescue around 300 residents.
There have been no reported deaths so far but Premier of New South Wales Dominic Perrottet said the flooding could get worse.
"Please don't be complacent," he told people in the Australian state on Tuesday. "Wherever you are, please be careful when you're driving on our roads. There are still substantial risks for flash flooding."
A water authority spokesman said "quite an extraordinary weather event" had overwhelmed the city's Warragamba Dam, overfilling the reservoir and leading to the spillages equal to all the water in Sydney harbour.
The latest storm will probably ease in Sydney from Tuesday as the coastal trough moves north, the Bureau of Meteorology said.
But the risk of flooding could remain throughout the week, with most river catchments already near capacity, even before the latest deluge. Some regions received 800mm of rain since Saturday, eclipsing Australia's annual average rainfall of around 500mm.
Winds up to 90 kilometres per hour are also forecast in several flood-hit places, raising the risk of falling trees and power lines.
"We're asking people across Sydney today to please stay at home unless you really need to leave the house," state Emergency Management Minister Steph Cooke said.
Battling rough seas, emergency crews continued their rescue operation on Tuesday to tow a bulk carrier ship that lost power off the coast of Sydney after tow lines broke in severe weather, officials said.
Major flooding is occurring at Windsor in Sydney's west, its third and most severe flood this year, according to the weather bureau.
Footage on social media showed submerged roads and bridges, while emergency crews rescued stranded people from partially submerged vehicles that became stuck in rising waters.
Nigel Myron, a Windsor resident, said he has an inflatable boat ready in case he has to evacuate, although he is looking to move back to his place once waters recede.
"At the end of the day, what can you do? It is what it is and we dust ourselves off from the ashes and rebuild after the floods have come and gone," Mr Myron told ABC television.
Notable salonnières of the Middle East through history
Al Khasan (Okaz, Saudi Arabia)
Tamadir bint Amr Al Harith, known simply as Al Khasan, was a poet from Najd famed for elegies, earning great renown for the eulogy of her brothers Mu’awiyah and Sakhr, both killed in tribal wars. Although not a salonnière, this prestigious 7th century poet fostered a culture of literary criticism and could be found standing in the souq of Okaz and reciting her poetry, publicly pronouncing her views and inviting others to join in the debate on scholarship. She later converted to Islam.
Maryana Marrash (Aleppo)
A poet and writer, Marrash helped revive the tradition of the salon and was an active part of the Nadha movement, or Arab Renaissance. Born to an established family in Aleppo in Ottoman Syria in 1848, Marrash was educated at missionary schools in Aleppo and Beirut at a time when many women did not receive an education. After touring Europe, she began to host salons where writers played chess and cards, competed in the art of poetry, and discussed literature and politics. An accomplished singer and canon player, music and dancing were a part of these evenings.
Princess Nazil Fadil (Cairo)
Princess Nazil Fadil gathered religious, literary and political elite together at her Cairo palace, although she stopped short of inviting women. The princess, a niece of Khedive Ismail, believed that Egypt’s situation could only be solved through education and she donated her own property to help fund the first modern Egyptian University in Cairo.
Mayy Ziyadah (Cairo)
Ziyadah was the first to entertain both men and women at her Cairo salon, founded in 1913. The writer, poet, public speaker and critic, her writing explored language, religious identity, language, nationalism and hierarchy. Born in Nazareth, Palestine, to a Lebanese father and Palestinian mother, her salon was open to different social classes and earned comparisons with souq of where Al Khansa herself once recited.
The five pillars of Islam
'Laal Kaptaan'
Director: Navdeep Singh
Stars: Saif Ali Khan, Manav Vij, Deepak Dobriyal, Zoya Hussain
Rating: 2/5
GIANT REVIEW
Starring: Amir El-Masry, Pierce Brosnan
Director: Athale
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MATCH INFO
Champions League quarter-final, first leg
Tottenham Hotspur v Manchester City, Tuesday, 11pm (UAE)
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UAE currency: the story behind the money in your pockets
Traits of Chinese zodiac animals
Tiger:independent, successful, volatile
Rat:witty, creative, charming
Ox:diligent, perseverent, conservative
Rabbit:gracious, considerate, sensitive
Dragon:prosperous, brave, rash
Snake:calm, thoughtful, stubborn
Horse:faithful, energetic, carefree
Sheep:easy-going, peacemaker, curious
Monkey:family-orientated, clever, playful
Rooster:honest, confident, pompous
Dog:loyal, kind, perfectionist
Boar:loving, tolerant, indulgent
UAE currency: the story behind the money in your pockets
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Uefa Champions League, last-16 second leg
Paris Saint-Germain (1) v Borussia Dortmund (2)
Kick-off: Midnight, Thursday, March 12
Stadium: Parc des Princes
Live: On beIN Sports HD