SYDNEY: Hundreds of residents in major regional towns across Australia's most populous state are being urged to leave homes as slow-moving floodwaters push downstream and the country's fourth major flood crisis this year rolls into a second month.

Authorities are urging residents to evacuate from parts of the New South Wales regional towns of Wagga Wagga, Gunnedah, and Forbes, collectively home to roughly 90,000. Flooding at Forbes, roughly 5 hours drive west of Sydney, could hit a 70-year high on Friday.

Across Australia's most populous state, emergency services conducted 15 flood rescues in the 24 hours to Thursday morning. One hundred and four emergency warnings are in place.

"It is a long list of rivers in flood in New South Wales, with our greatest concern at the moment being for the Lachlan River at Forbes," the state's emergency services senior manager Ashley Sullivan said in a video statement.

"We are expecting major flooding in the next couple of days equivalent to probably the 1952 flooding in that area."

Flood-weary residents across Australia's southeast are enduring the fourth major bout of flooding this year. Authorities have announced at least A$2 billion ($1.3 billion) in disaster relief to help thousands of residents repair homes and in some cases move from flood-prone areas.

In the state of Victoria on the banks of the Murray, Australia's longest river, residents at Echuca are still unable to return home as emergency services warn major flooding that began two weeks ago will persist for at least another week.

Blue skies have replaced rain across most of New South Wales and Victoria with little rain forecast for the weekend. But emergency services warn rivers will keep rising for days as water seeps into already swollen floodwaters moving slowly downstream.