As oceanside homes in the Central Coast town of Wamberal lost pieces as they were undermined by the force of the Pacific Ocean during last week's East Coast Low - as in Collaroy earlier this year - some in the Illawarra wondered how close we might come to a similar fate.

What stands in Wollongong and Shellharbour's favour, in comparison with other areas, is that much of the immediate foreshore has been protected from housing development, reserved as public or Crown land. Most coastal suburbs have homes on the landward side of a road, or rocky cliffs.

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Whether it be by design or luck - in the words of Wollongong's Lord Mayor Gordon Bradbery - much of this coast may better stand the test of time and tide.

But not forever. Shellharbour City Council (SCC) will soon formally consider its options for protecting Warilla's "Millionaire's Row" at Little Lake Cres, where homes were built on the sea side of the road.

In Wollongong, little land behind beaches is regarded as high risk yet. But by 2050 most of the beaches from Stanwell Park to Windang are regarded as being at "extreme risk" of erosion.

Much of Wollongong also has the advantage of not having been built on sand dunes, as is Wamberal.

Coastal scientist Verity Rollason said times have changed since many coastal towns were planned.

"We just didn't understand our coastline and coastal processes ... how some of these these beaches were either transient or very dynamic, at the time those beaches were subdivided and built on," she told ABC Radio.

"We've learned now, and we try out best to do a better job with planning, but those old issues do remain."

The challenge is now to make smart moves on erosion even if a city hasn't seen severe storms for years.

Both Wollongong and Shellharbour's councils have studied these risks.

By 2050 Lawrence Hargrave Dr is threatened at Austinmer, while a medium risk is described for Beach Dr behind of Woonona Beach. Low-lying areas behind Thirroul beach are vulnerable to the extent a sea wall along half the beach was one option considered in recent years.

Estimates of sea level rises from climate change, used by Wollongong City Council, include a projection of a 0.45-0.5m rise by the year 2050, and 0.9m by 2100.

In Shellharbour, 10 housing lots were identified as being at "high or extreme" risk from erosion - nine on Wollongong St and one on Towns St, with another 57 potentially at risk, but "unknown" (52 on Little Lake Cres, five on Junction Rd).

By 2050, if no further steps are taken, it is projected another 14 lots will be added to the "high or extreme" risk category, and by 2100 the figure would be 37 lots.

The Beachside Tourist Park at South Beach is regarded as already high to extreme risk, while the Shellharbour Surf Life Saving Club would reach this mark by 2050.

The "unknown" related mainly to Little Lake Cres, where the structural integrity of the sea wall was not fully understood when the plan was completed in 2018.

SCC general manager Carey McIntyre said the work had since been done.

"In response, council has undertaken renewal works including the importing of rock and placement in required locations at a cost of $170,000 in 2019," he said.

"In April 2020, major maintenance of the rock armour was undertaken again after an east coast low, generated large swells that impacted the revetment wall."

A cost-benefit analysis for long-term Warilla Beach protection options had been completed and would be presented to council soon.

Mr McIntyre said subdivision layouts as far back as the 1800s had maintained much of the foreshore as council-managed land.

"Therefore development has been limited to public infrastructure such as pathways, parking, drainage and surf clubs," he said.

"Where urban development has occurred closer to the foreshore, there have been designated setbacks to ensure foundation stability and reduced visual impacts."

Cr Bradbery said decisions over time, from local and state authorities, had help Wollongong development stay back from the sea.

"Whether it be by design or just good luck, that has been to the advantage of not only Wollongong [but also] Kiama, Shellharbour and Shoalhaven," he said.

He said decisions on dune management - trees and shrubs which hold the land in place, help - even if it interrupts the view.

"Many people have criticised us about the coastal vegetation but that has been one of the reasons why we've been able to save a lot of those beaches being eaten away by big seas," he said.

"I know it's unsightly for some ... but it has also protected our city from these sorts of situations."

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