Bill Pile, one of the key figures in the estimated equivalent $1million community-led reconstruction, said he was "sad and disappointed'' to see the road "sunk down'' significantly.
"It's very disappointing for the people that put the work into it to see their work go like this.''
Haven St was closed to through traffic in August 2013 when heavy rain collapsed the 400m section.
It remained closed for two years, but the community rallied, and for five months last year a volunteer effort rebuilt the road.
It was reopened and the final seal went down at the end of November.
Mr Pile claimed the Waitaki District Council rushed sealing the road, failing to allow the "400 truckloads'' of rock put in place to settle.
He said the road had sunk exactly where it was expected to sink.
"That is why we didn't want the road done until after Christmas. We - the people who did the job, about 10 of us - we said ‘no, we don't really want it sealed yet, we would rather it be done in the New Year','' he said.
"They did it too soon.''
However, Richard Hanrahan, of Moeraki, called for "patience'' and said Mr Pile's views were not shared by all the group that rebuilt the road.
"We didn't say we didn't want it sealed, we just said we didn't expect them to seal it,'' Mr Hanrahan said.
"But then the explanation was that by sealing it, it would keep the water off the road and push it into the drain network that was there.''
Waitaki Mayor Gary Kircher said the roughly $150,000 the council spent on the project would be followed through on.
"Ratepayers right across the district have contributed significantly to that road,'' he said.
"We didn't put money into it just to walk away from it - it's quite the opposite.''
Council roading manager Michael Voss said it was not a mistake for the council to seal the road when it did.
"No ... the community wanted it sealed before Christmas, to make it look a really good job. And when we seal the road, we actually do tighten up the surface, get it properly shaped, so any water that comes on to it ... is better controlled. And the bitumen itself is a waterproofing - it doesn't allow water into it.''
He said the council would do the remedial work "as soon as we can'' - 30kmh speed limit signs would be put in place, crack sealing, and some drainage work would be done.
The good news was the concrete rails put in place during the rebuild were all still "true'' and the embankment itself showed no signs of slipping.
