More than 2000 additional Newcastle homes have been classified as flood-affected in a new draft study looking at climate risks.
City of Newcastle has placed its draft Throsby, Styx and Cottage Creeks Flood Study on exhibition. It replaces the previously adopted Throsby, Cottage and CBD Flood Study from 2008.
The mapping identifies an extra 2079 residential, 140 commercial, 39 industrial and 79 other properties as flood risks compared to the 2008 study, while 354 properties are no longer classified as flood affected due to modelling technology improvements.
Letters will be sent to all properties that will experience a change in flood classification.
Development applications for properties identified as flood-affected will be required to meet flood management controls such as using water-resistant materials for parts of a building below the flood planning level.
Labor councillor Deahnna Richardson said she believed "the community would probably be fairly alarmed" by the numbers, particularly in relation to insurance premiums.
"But it's absolutely necessary that we update these maps so that we have an accurate understanding of what exactly our risk is, so that we can protect lives and property in the event of a severe flood event," she said.
"It's probably worth noting that insurance companies do their own modelling around flood risk and they have their own actuaries who do this sort of research.
"And the risk in terms of this flood mapping for residents... isn't going to affect insurance premiums until we're very close to 2050, which is the projected timeline for this particular study."
Greens councillor Charlotte McCabe said approximately 30 per cent of Newcastle properties were flood affected.
"Measuring and predicting flood impacts is a complex process and that complexity is increased in our city because of the confluence of ocean flooding in low-lying areas together with rainfall events," she said.
"This is going to be an extremely long-term issue and as councillors I think we all need to become experts in this topic so that we don't ourselves contribute further to the misinformation or misunderstanding that's already circling out there in the community on a topic that is extremely sensitive for the people who are currently being affected.
"So many peoples premiums have already been directly impacted and become completely unaffordable.
"Climate change is here and its impacts are not going to be easy for anybody. We know that they will be the hardest for the most vulnerable in our community."
Consultancy firm Rhelm completed the flood study, which "aims to provide a better understanding of the full range of flood behaviour and consequences".
Hexham and Woodberry swamp areas will be assessed next financial year, and afterwards the council will complete a flood risk management study and plan.
Flood risk management actions will then be implemented through the council's capital works program.
