Heavy rain is lashing vast swathes of Sydney, causing rivers to rise and subjecting thousands more people in flood-stricken areas to evacuation orders or warnings.

The flood emergency now stretches from the Central Coast to the Illawarra, with 97 evacuation orders and 60 warnings covering 45,000 people — up from the 32,000 affected on Monday.

The majority of orders cover areas surrounding the Hawkesbury, Nepean, Georges and Woronora rivers, all of which are still rising.

Major flooding continues at Windsor, Sackville, Richmond, North Richmond and Wisemans Ferry to the northwest of Sydney.

The Bureau of Meteorology has warned of potential flash-flooding and high winds, with gales possible for the Hunter and Sydney coasts.

Rain is forecast for the rest of the week, extending to the northern part of the state which is still reeling from recording-breaking floods in February, March and April.

State Emergency Service spokesman Ashley Sullivan says the situation remains volatile, with the SES receiving 475 calls for help overnight.

The SES performed more than 100 flood rescues — mostly people stranded in cars after driving into floodwaters or those who became trapped as rivers and creeks rose quickly.

“Certainly with the persistent rain we are receiving, the threat will remain into today and tomorrow,” Mr Sullivan told ABC TV on Tuesday.

“Even when it does stop raining, the flood threats will continue,” he said

Authorities are particularly concerned about the Hunter Valley over the next 48 hours, as the Hunter River system swells.

Emergency Management Minister Steph Cooke says there are about 400 people in evacuation centres in the high-risk areas, and 150 in emergency accommodation.

She is asking people across Sydney to stay at home “unless you really need to leave the house” as damaging winds are expected.

“We’re not out of the woods yet,” she told ABC TV.

Power was cut to around 10,800 homes overnight because of the rising waters and damaging winds.

Endeavour Energy said it made the difficult decision on Monday night to cut power to more than 4000 homes and businesses in the Hawkesbury region between Wilberforce and Wisemans Ferry.

It will likely take days for flood waters to recede and roads to re-open before power can be restored.

Damaging winds meant power was cut to another 5000 customers predominantly in the Upper Bluer Mountains between Leura and Blackheath, and the Shoalhaven region between Jamberoo and the Upper Kangaroo Valley.

Since the start of the event last week the SES has responded to more than 5000 requests for help.

BOM senior meteorologist Jonathan How said some parts of southern Sydney copped as much as 200mm of rain overnight.

“We’ve seen absolutely incredible rainfall totals, and a number of places have not only broken the daily July records, but the daily annual records – particularly Campbelltown which has recorded its wettest day of any month over the last couple of days,” he told ABC TV.

The rain is predicted to ease on Tuesday afternoon but fears of flash-flooding remain.

Meanwhile, joint disaster funding has been announced for 23 local government areas in Sydney and parts of NSW.

Some areas are expected to approach or exceed flood levels of recent events in March 2021, and February, March and April of this year.

Minister for Emergency Management Murray Watt said the federal and NSW governments were working together to ensure affected areas get financial and other assistance as soon as possible.

“We have seen some of these impacted communities being hit by floods for a third and fourth time in 18 months, which is extremely distressing to the residents,” he said.

– AAP