A long line of World War II era tank traps have been exposed on Stockton beach to a point many residents have never seen before.
Some of the traps, which are also known as tetrahedrons, remained visible on Monday after dozens were exposed during the weekend's big swell.
A photo taken by Stockton resident Symon James near Fort Wallace on Sunday showed a line of the reinforced concrete blocks more than 200 metres long.
Stockton Surf Life Saving Club president Callan Nickerson said he had never seen that many of the relics.
"I've never seen them exposed like that before," he said. "It's pretty unreal."
Mitchell Street resident Alan Metcalfe said it was "quite common" to see some of the tank traps exposed in the area but he had seen "no more than 100 metres" of them in more than 30 years living on the peninsula.
"I've been here 32 years and I haven't seen them that bad," he said.
Waves were again expected to surge across the beach in Stockton's north at high tide on Monday night where sand had been stripped over the past few days.
Most of the region's beaches continued to resemble a washing machine on Monday with a peak swell of more than five metres recorded off the NSW coast, the result of a complex low-pressure system in the Tasman Sea.
The BOM had issued a severe weather warning for damaging surf in the Hunter, Central Coast and Mid North Coast regions.
"Our wave buoy off Crowdy Head is only reporting patchily, but the one off Sydney is still showing significant wave heights between four-and-a-half to five metres and maximum wave heights up to seven or eight metres," BOM meteorologist Rebecca Boettger said on Monday afternoon.
"It's all being driven from the low-pressure system which is sitting out in the Tasman giving us really strong winds along our coast and also large swell.
"That low is expected expected to slowly weaken over the next 24 hours."
Rain was expected to fall on coastal areas of the region again on Tuesday after a decent soaking on Monday.
The Bureau of Meteorology was predicting up to 20mm in parts of Lower Hunter from "lingering showers", Ms Boettger said.
Students returning to school on Monday were greeted with wet and wild weather that continued throughout the day.
The temperature barely rose above double figures in some areas. Merriwa dipped to only 1.6 degrees yesterday morning, while Murrundi Gap reached a high of only 10.4 degrees.
Nobbys reached a high of 15.1 degrees, Cessnock 16.4, Maitland 15.9, Lake Macquarie 15.6, Singleton 15 and Scone Airport 15.1.
More than 10mm of rain had fallen across much of the Lower Hunter between 9am and 6pm on Monday, including 32mm at Blacksmiths, 17mm at Broadmeadow, 16mm at Seaham and 15mm at Nobbys.
A regional high of 50mm had been recorded at Careys Peak on the Barrington Tops as of 6pm.