Premier Dominic Perrottet says 85,000 people are now subject to evacuation orders and warnings.

The State Emergency Service has issued 108 evacuation orders and 56 evacuation warnings.

Overnight the Hunter and Central Coast were hit hard as communities were evacuated and a flood watch has been issued for the Mid-North Coast as the weather system shifts north.

The Hawkesbury-Nepean region in Sydney’s west has once again been hit by major flooding this week.

SES Commissioner Carlene York says the agency had another busy night, conducting 21 flood rescues and urged people to follow warnings and orders to evacuate.

“People have taken a risk and remained in those houses and then found out the risk is too great, and we have to go in and save those families,” York said.

Eleven evacuation centres have opened to support people ordered to flee their homes, including new ones in the Hunter and Central Coast at Cessnock, Singleton and The Entrance.

Flood Recovery Minister Steph Cooke said some 523 people have already sought refuge in the centres.

The Hunter River is being monitored closely at Singleton, where major flooding is expected.

The Bureau of Meteorology’s Jane Golding said the river could reach up to 13.8 metres and the risks will remain even once the weather clears.

“(We are) starting to see some some fine weather on the horizon, but (it will) take a bit of time for the floodwaters to come down,” she said.

The Hunter has already seen flooding worse than in March this year and last year at Bulga and Wollombi on the Wollombi Brook, Golding said.

The BOM is predicting an easing of the severe weather on Thursday as the low pressure system tracks out to sea.

“Friday could be quite a nice day,” she said.

Overnight people in the Hunter community of Broke were cut off by rising floodwaters.

The SES has 1000 volunteers supporting isolated communities, and has requested assistance from other states, expected to arrive on Wednesday.

Prime Minister Anthony Albanese said another 150 Australian Defence Force members will join the 100 already on the ground on Thursday,

A third helicopter will be available for night time operations from Wednesday evening, likely operating in the Hunter region, he added.

Cooke said damage assessments will begin in Sydney’s west as floodwaters recede around the Georges River and Upper Nepean River.

However, she warned residents to wait until they’ve been given the word from the SES to return home.

“Whilst it might be tempting for people to return home we’re really asking you to respect those evacuation orders,” Cooke said.

“There’s a reason why they are in place.”

Some properties have been isolated for days and infrastructure such as roads, power, water, and telecommunications are damaged.

Albanese and Perrottet will visit deluged parts of the Hawkesbury on Wednesday – a region that has endured four floods in the past 18 months.

The prime minister has announced disaster recovery payments of $1000 for eligible adults and $400 for children will be available, with applications open from 2pm on Thursday.

“This is on top of the joint arrangements being made available through NSW and the Commonwealth,” Albanese said.

Affected New Zealand citizens will also have some support available.

Mr Perrottet said the focus remains on protecting lives and properties, but attention will shift quickly to support and recovery.

Grants are available again, and the approval process has been improved to make sure money gets to people who need it faster, Mr Perrottet said.