Warnings of hazardous surf and strong wind were issued for the Newcastle coast on Thursday, as huge waves smashed Stockton.
The swell at Stockton hit a high of 5.3 metres, before falling to four metres.
The Bureau of Meteorology warned on Thursday morning that the "heavy surf may lead to localised damage and coastal erosion".
The surf in Newcastle was up to two metres high.
A bureau statement said beach conditions "could be dangerous and people should stay well away from the surf and surf-exposed areas, particularly south-facing coastlines".
Long-time Stockton resident Neil Jackson has watched the suburb's beach slowly disappear over the last 30 years.
"It's hard to negotiate a walk along the beach," Mr Jackson said.
The beach spot where he used to sit in a deck chair and have a beer is now under water.
Beach nourishment of 130,000 cubic metres of sand was delivered to Stockton last October and November as part of a $6.3 million project.
In December, a state government blueprint was revealed that outlined five steps to fix erosion at Stockton through a $21 million commitment.
Erosion at Jimmys Beach near Tea Gardens also accelerated on Thursday.
Mid Coast Council crews were forced to remove a power pole before it was swept into the massive swell.
Owners of multi-million dollar homes along The Boulevarde watched anxiously as the sea gnawed away at the narrow sand buffer that separates them from the beach.
Local resident Gordon Grainger said he feared a concrete and polypropylene "sausage" that had been installed under the road in 2015 was giving way.
"It looks like the water is getting in behind it now, which is a real worry," he said.
University of Newcastle Associate Professor Iftekhar Ahmed, a climate change adaptation expert, said erosion from heavy seas would increase in future.
"We have little control over what's happening because of climate change," he said.
While greenhouse gases could be reduced, he said "it's not going to change things quickly".
"There are natural cycles, but it's exacerbated by climate change - the sea level rise that's happening," he said.
"This is not going to go away. Icebergs won't freeze again. All you can do is try to keep it at the same level - that's the optimistic scenario."
A/Prof Ahmed believes the Newcastle coast will face a reckoning at some point in future.
"There's a lot of discussion about managed retreat due to climate change and sea level rise," he said.
"That has a social cost with people having to be relocated. I was in Singapore for a study project and they have massive problems," he said.
"They have built incredible coastal barrages for sea level rise and coastal floods. That's an option, but it's very capital intensive."
The barrages were "safeguarding a city of six million".
"That's a different ballgame, so it's worth the investment," he said.
The swell at Stockton is forecast to fall to three metres on Friday and two metres on Saturday.
Nobbys recorded a top wind gust of 57km/h at 3.18pm on Thursday, while the temperature hit a low of 10.2 degrees at 5.54am and a high of 14.6 at 1.29pm.
On Friday, Newcastle can expect a partly cloudy day, with a medium chance of showers, most likely in the morning.
Winds are expected to be 15 km/h to 25 km/h, before easing in the evening.
