Stabilising the collapsed section of the South Newcastle sea wall will be no quick fix and may cost up to $1 million, an experienced civil engineer believes.
Sunday evening's high tide gouged further material from the wall, which initially collapsed on Saturday night.
Project engineers assessed the damaged area on Monday morning.
An excavator that was left perched over the gaping hole was also safely retrieved.
A City of Newcastle spokeswoman said the collapsed section of sea wall was to be replaced as part of the upgrade to South Newcastle Beach.
"Investigations are continuing to determine the most appropriate solution to progress with work on its replacement," she said.
"The damage to the sea wall will not impact the overall delivery of the project. Any necessary works and their associated costs will be managed in accordance with the contract."
The area where the collapse occurred is at the southern fringe of the $10-million-plus skate park project.
A civil engineer who viewed the damage on Monday said he believed new pylons would need to be sunk to secure the century-old retaining wall before work could begin on building a new section of sea wall.
"There's no way it can just be filled in because the whole structure has been compromised," the engineer, who did not wish to be named, said.
He estimated the work could add about $1 million to the cost of the project.
Meanwhile, Stockton Beach was spared the worst of the weekend's conditions, with no new erosion occurring.
"Erosion prevention measures were effective at Stockton over the weekend and rock bag placement at the Barrie Crescent site at Stockton Beach has restarted as conditions have eased," the City of Newcastle spokeswoman said.
A survey is also underway to determine the potential for sand to be taken from the south arm of the Hunter River to be used for mass sand nourishment.
The project involves assessing sand quality against the sand management guidelines to confirm it is suitable for use at Stockton Beach. It also includes the development of the beneficial reuse planning pathway and approvals needed to place sand on Stockton Beach.
Researchers are also examining the suitability of offshore sand for beach renourishment.
The council is currently assessing the feasibility of four coastal management schemes (maintenance nourishment, artificial headland, artificial reef and sand back passing) which aim to prolong the benefit of mass sand nourishment after the sand arrives at Stockton.
