Plans to build extra homes on high-risk flood plains could be shelved across NSW after the state government axed the rezoning of land on Sydney's outskirts.
The decision to scale back the developments on the city's northwestern fringe followed a state government flood report that declared there would be a "risk to life" in the case of a mass evacuation.
Planning Minister Paul Scully said the government was considering extending the measure to any dangerous flood plain area, although he declined to give a clear definition of what that would entail.
"It's one, not unreasonably, that puts lives at risk," he told a budget estimates hearing on Friday.
"The definition of dangerous will vary based on the frequency, the severity (and) the capacity for people to leave."
The state government on Sunday announced it was scrapping rezoning plans for Marsden Park North and parts of West Schofields, which were due to be developed with more than 10,000 homes.
Plans for a new Riverstone Town Centre will also no longer go ahead.
The decision followed the release of a flood evacuation report, which found there was a risk to life in areas such as the Hawkesbury-Nepean basin.
Mr Scully on Friday described the area as the plain with the highest unmitigated flood risk of anywhere in Australia.
The report said the number of people unable to evacuate from the region in the case of a flood increased significantly if all potential development was to occur.
"For example, for a 1-in-500 chance per year flood (similar to the worst flood on record), the risk to life would increase from an estimated 980 people under committed development to around 23,700 people by 2041," it read.
Opposition Leader Mark Speakman called on the government to be transparent about its modelling, referring to criticisms of the evacuation report by former NSW Police deputy commissioner Dave Owens.
"Obviously governments cannot be reckless and put people in harm's way," he told ABC Radio.
Pressed at estimates about whether the government would stop housing developments in other flood-plain regions, such as Clarence Valley in the Northern Rivers, Mr Scully said he was "looking at all options".
"Where there are cases where we believe there should be an intervention, that will happen," he said.
"As a broader policy work, that continues.
"We absolutely won't put lives unnecessarily at risk by building on dangerous flood lines."
Mr Scully said if housing developments did not go ahead, the land could be used in alternative ways.
"Just because you can't use a piece of land for residential use, doesn't mean you can't use it for other uses ... there's sporting fields, there's biodiversity, there's the potential for areas to be zoned as industrial or commercial," he said.
A major buyback scheme is under way for people affected by catastrophic flooding in the Northern Rivers area.
