Large swaths of Western Sydney remain on high alert, with heavy rainfall tipped to send water roaring over the wall at Warragamba Dam this weekend.

Emergency Services Minister David Elliott told The Saturday Telegraph there is "obviously a risk that the dam will spill over", sending communities in the Hawkesbury-Nepean area scurrying to higher ground.

Greater Sydney is expected to cop 60mm-120 mm on Saturday, ­according to the Bureau of Meteorology, with 90mm enough to open the dam floodgates.

A severe weather warning remains active on Saturday for people in Hunter, Sydney, Illawarra, Southern Tablelands, Australian Capital Territory, and parts of the Mid-West Slopes and Snowy Mountains weather districts.

Police announced a Public Information and Inquiry Centre had been activated on Saturday morning to support the severe weather operation.

The inquiry centre will provide information on the severe weather and flooding until at least 5pm on Monday. The number is 1800 227 228.

The main areas for concern are St Albans, Marsden Park, Richmond and parts of Windsor, with communities warned to sandbank properties, move livestock and prepare to leave.

"This just confirms the caution that I put to Sydney Water over many, many months now that they should not leave the dam at 100 per cent or near 100 per cent," Mr Elliott said.

"I think it creates too many risks."

The State Emergency Service said "we are also liaising with our partners at Water NSW where they will advise us accordingly should the dam spill".

At Kindee Bridge, west of Port Macquarie, the Hastings River has surpassed the record major flood level from February 2013 and could keep rising.

Between 9am Friday and 5am Saturday, Delward recorded 373mm of rain, Redoak received 343mm, and Upper Rollands Plains recorded 250mm; including 125.8mm in three hours.

A service station at Telegraph Point was inundated, with locals working together to transfer an ­injured man from a boat to a car in the middle of the street.

Footage also emerged of cars abandoned in flood waters and a lawn bowling green at Comboyne that resembled a pool.

An evacuation order in place for Kempsey CBD was being assessed at 8pm for possible escalation, and an evacuation order had been issued along Lower Macleay due to the rapid rise of waters.

The Hastings River hit record levels at Kindee Bridge and Wauchope and it was not believed to have yet peaked. Emergency services said evacuations would be required there.

Flooding was declared major along the Gloucester River at Gloucester about 8.30pm on Friday, while the Camden Haven River is expected to break the record set in 1978 at Laurieton early on Saturday morning.

The Pacific Highway was closed in the region and there were numerous communities isolated by floodwaters.

Since Thursday, the SES has ­responded to 1780 requests for ­assistance statewide. There have been 330 requests in the Sydney metropolitan area and those numbers are expected to skyrocket today.

Mr Elliott said there were 10,000 SES volunteers on standby, but added that he had had a gutful of people putting lives at risk by trying to cross floodwaters.

"SES volunteers do their job without any sort of recognition or reward, so I actually think it is the height of arrogance for people to ­ignore the flood warning," he said of the 41 flood rescues completed since Thursday.

"You wouldn't want to walk into a bushfire so why would you go through flood waters?"

Seawalls along the Northern Beaches (Collaroy) and the Central Coast (Wamberal) remain unaffected for now, according to local ­councils.

Along the Central Coast emergency crews are in the process of ­removing between 2000 and 20,000 tonnes of sand and earth from lakes including Copacabana, Avoca, Wamberal and The Entrance.

Fears remains that coastal lakes at high tide will flood homes along the waterfront.

Similar works are being carried out on northern beaches lagoons.

Between Sunday and Thursday next week Sydney is expected to ­receive a maximum of 98mm of rain, with the majority tipped to fall ­before Wednesday morning.

Areas along the north coast will receive the most rain next week, however Orange, Wagga Wagga and Jindabyne will also get hit midweek.

Originally published as Flood warnings for Sydney as rain buckets down