Chas Keys said councils and governments placed a lot of emphasis on whether new developments could become ­inundated, but not enough attention to ­surrounding infrastructure to make sure those new suburbs would not become ­isolated during floods.

The former SES Deputy Director General said isolation led to a range of health, emergency and business-related problems.

He said this was evident during last year’s April super storm, when Gillieston Heights was isolated for several days after Cessnock Road was flooded at Fishery Creek and Testers Hollow.

“Traditionally, our urban planning has taken note of inundation as an issue,” Mr Keys said.

“But there are problems that happen not just with inundation, but with isolation. 

“In Gillieston Heights in 2015 there was a whole slough of medical evacuation. People weren’t able to get to work so there were economic impacts, kids weren’t able to go to school – a com­munity was cooped up in an unfamiliar ­situation, not able to live their normal lives.”

With continued growth expected at Gillieston Heights and potential growth at other areas such as Wallalong, Mr Keys said there needed to be a focus on providing road infrastructure that would stop isolation.

“I think the answer is roads,” he said.

“In a hundred years we’ll probably have both of these: one will be either a viaduct or bridge at Testers Hollow and a road that will go around to the west, which is probably the cheapest option.”

His comments came in the first week of a Fairfax Media campaign calling for the frequent flooding issues at Cessnock Road, Testers Hollow, to be fixed.

The key route between Maitland and Cessnock was closed for five days after two days of heavy rainfall in the Hunter earlier this month.

It was the second time the road had been cut in nine months.