"The road is along the edge there and there is a bit of a drop - between half and one metre. It's cut into the northern end of the car park," Mr Sutherland said.
The temporary rockwork installed earlier this year further south towards the tiphead had held, despite the sea washing over the top yesterday, he said.
A long-time Cobden resident said on Friday there was a significant risk to those using the car park and the potential risk to Jellyman Park and nearby residents if the sea broke through.
He described the $25,000 of temporary rockwork placed there by the council earlier this year as "ridiculous"as that work was now "floating out to sea".
On Friday morning there was nothing to warn visiting members of the public of the subsidence risk at the edge of the car park, which was visibly falling away in the high tide.
The ground was cracking and falling away within metres of where a campervan had parked. A 100m stretch of the foreshore was crumbling away with the incoming tide, creating a steep drop down to the beach.
Mr Sutherland said he could understand public concern.
"The big picture issues need to be considered moving forward. The car park is one thing, but there's assets and the town of Cobden to consider as well; that's why we've involved the regional council." The remedial work needed to protect the area in the meantime was "not insignificant".
- Greymouth Star