"The stories that we've heard up here, the images that we're seeing, do not do justice to what we're seeing on the ground," the premier said from Lismore on Saturday.
"The strength and resilience of the people of Lismore, the strength and resilience of the people of the Northern Rivers, was on full display today.
"But after everything we've gone through as a state over the last few years I know we will get through this, as challenging as it seems."
Mr Perrottet said his government was "not going to spare a dollar" when it came to flood recovery
The death toll from floods in NSW now stands at six, with the most recent fatality a man believed to be in his 40s whose body was found near Terragon, south of Murwillumbah, on Friday afternoon.
The premier said housing and homelessness would be a significant challenge in northern NSW through the recovery effort.
"People are hurting across the state, people are hurting in this particular area," Deputy Premier Paul Toole said.
"This is a catastrophic event and we know that they need help right now.
"This is going to be a long journey but the NSW government will stand side-by-side with these communities."
Minister for Emergency Services and Resilience Steph Cooke became emotional addressing criticism of State Emergency Service workers, calling it "unwarranted".
"I know the SES has come under a bit of heavy fire in the last few days," Ms Cooke said.
"You guys have done an incredible job particularly up here in the Northern Rivers."
She said SES volunteers worked up to 20 hours a day carrying out rescues and helping people to safety.
The minister said the SES had her full support and the support of the NSW government.
In the Northern Rivers, some locals claimed on social media people in regional areas had been poorly serviced by the SES.
Ms Cooke, who will soon take on the role of flood recovery minister, said NSW had asked the federal government for 5000 Australian Defence Force personnel to help with the clean up.
She said a group of 900 would arrive on Sunday.
"We're really hoping that that does ramp up closer to that 5000 mark really quickly, and we would really welcome that.
"When you see the task at hand in the streets of Lismore, we need every one of them."
The cost in NSW is now more than $240 million, according to the Insurance Council of Australia, while estimates taking in Queensland claims reached more than $1 billion on Friday.
The ICA said it had received 67,537 flood-related claims, 24 per cent from NSW and 76 per cent from southeast Queensland.
The federal government has meanwhile extended one-off relief payments to another 28 local government areas, Emergency Minister Bridget McKenzie and Government Services Minister Linda Reynolds said.
"We continue to closely monitor the flood emergency and our hearts go out to those people whose lives are being devastated," Senator McKenzie said in a statement.
"We have made financial help available now because we know the economic impact of disasters like these are felt long after the flood water recedes."
Mr Toole earlier announced farmers will be able to access $15,000 immediately through Commonwealth-State Disaster Recovery Funding Arrangements.
Grants of up to $75,000 are available for primary producers in disaster-declared LGAs.
