SYDNEY, March 3 ― Australian authorities today issued fresh evacuation orders for thousands of Sydney residents after heavy rains triggered flash flooding in Australia's largest city, with officials warning of worse to come.

The country's east coast has been battered by a severe weather system that has cut off entire towns and submerged hundreds of homes and farms as it has moved south from Queensland state over the past week. Parts of Sydney and some neighbouring regions are forecast to get a month's rainfall today.

“We do believe that things will get worse before they get better,” NSW Premier Dominic Perrottet said during a media briefing today, as he flagged some half a million people in the state would be affected by evacuation orders and warnings.

“Many people are waking up today to see much of our state under water. It has been an incredibly difficult evening.” Tens of thousands of Sydney residents were ordered to evacuate in the middle of the night yesterday.

Perrottet said the floods would likely be worse in many places than last year's, which were the worst in 60 years.

Some areas on the city's west received around 100 mm (4 inches) of rain over the last 24 hours and the weather bureau says more is on the way with some places to get up to 200 mm today. March's mean rainfall in Sydney, home to more than 5 million people, is around 140 mm.

“If you are asked to leave your home, please do so, please do not put yourself or your family at risk,” New South Wales Emergency Services Minister Stephanie Cooke said. Emergency crews had received more than 1,400 calls in Sydney and conducted dozens of flood rescues.

The second year of flooding comes as the La Nina weather pattern, typically associated with increased rainfall, has dominated Australia's east coast summer. Rivers and catchments were already near capacity before the latest drenching after steady rains over the last few weeks. ― Reuters