NSW Premier Dominic Perrottet says "things will get worse before they get better" as 500,000 residents across the state are ordered to leave their homes with heavy rainfall expected today.
A main road is blocked by flood waters on the bank of Georges river on March 3, 2022, as Sydney faces its worst flooding after record rainfall caused its largest dam to overflow. Photo: AFP
There are currently 76 evacuation orders in place covering 200,000 people and 18 evacuation warnings covering nearly 300,000 people.
The east coast low off NSW is expected to impact Sydney, the Central Coast, Hunter and southern parts of the mid-north coast today, bringing heavy rainfall.
The Bureau of Meteorology (BOM) said the weather system would bring 50 to 150 millimetres of rainfall, but some areas could receive totals up to 200mm.
Major flooding has already been recorded at Menangle and North Richmond on Sydney's outskirts.
Penrith and Windsor have seen moderate flooding so far, although Windsor could experience river rises which cause major flooding.
"Many people are waking up today to see much of our state underwater," Perrottet said.
The situation, he warned, was about to get worse with water levels in some areas forecast to exceed those seen in last year's devastating floods.
"We do expect particularly in the Hawkesbury region that the floods will be worse than they were last year and that we will see more torrential rain and flooding in Newcastle and Hunter over the course of the day."
The premier said the government's Crisis Policy of Cabinet committee would be convened today to oversee the flood evacuation and recovery operation.
"It has been a very difficult three years here in New South Wales whether that be on the back of drought, fires, floods, floods again on top of the pandemic, but our people have stood tall," he said.
Evacuation orders were issued this morning for flood-affected parts of the city with thousands of people living along the Hawkesbury River in Sydney's north-west and the Nepean and Georges Rivers in the south-west told to evacuate by 9am.
"The issue with a lot of this rain is the fact the majority of the ground in the whole of NSW is already completely saturated," Greg Nash from the NSW State Emergency Service (SES) said.
"What this rain will likely do is cause flash flooding in areas because water simply won't have anywhere to go."
More than 100mm of rain fell over parts of Western Sydney overnight.
More rain for flood-ravaged Queensland
Storms bringing lightning and torrential rain have hit parts of south-east Queensland already devastated by flooding, and the Bureau of Meteorology (BOM) warns there could be more later today.
Floods from an overflowing Oxley Creek inundate roads at Rocklea, Australia's Queensland state on February 26, 2022. Photo: AFP
The warning of more severe weather has prompted more evacuations and Premier Annastacia Palaszczuk to ask parents in the northern part of Moreton Bay, Sunshine Coast, Wide Bay and Bundaberg regions to collect their children from school.
"This is a serious situation," she said.
"It is extremely unstable weather conditions and as a precaution, we would like our people to collect their children when they think it is safe to go out in the road and do so but they are safe at school until they can come and collect them."
Conditions will be volatile for the next 24 to 48 hours across the state's south-east corner, the Premier said.
BOM forecaster Laura Boekel said conditions were "very dangerous and potentially life-threatening" in the south-east of the state.
-ABC