A stone wall which made up part of a historically significant anchor pit used by the old Luggate Ferry has been damaged in the past month.
Kopuwai Consulting archaeologist Matthew Sole discovered the damage to the site last week.
Mr Sole has written a report on the archaeological significance of the area on the left bank of the Clutha River close to the Red Bridge as part of plan from the Luggate Community Association to improve the area.
It was distressing such an important site had been damaged, he said.
"It’s a disappointing setback to a significant feature among a regionally significant site of early transport history."
It was hard to know why someone would vandalise the wall, which meant it could have been an accident, he said.
"Someone could have thought they were tidying the place up and started moving the rocks around, which is why putting up signs around these type of sites is important."
Heritage New Zealand archaeologist Matthew Schmidt said people needed to know it was an offence under the Heritage Act to disturb a historical site and they could be prosecuted if found doing so.
"We are more about education than prosecution so it would be nice if the person who did this would come forward so we could educate them on what the situation is," he said.
The wall would most likely be rebuilt which would take away some of the historical significance, Mr Schmidt said.
"It’s goes from being an actual piece of history to more of a re-creation of history, which is pretty disappointing."
In the past 10 years, Mr Schmidt said he knew of five people who had been prosecuted because they had disturbed historically protected sites.
Luggate Community Association chairman Graeme Perkins said he could not understand why someone had decided to disturb the old stone wall.
"It’s not a big area of wall but it was original and did have quite a bit of historical significance for the area," Mr Perkins said.
Work had already started to make the area near the Red Bridge more attractive, so it was disappointing someone had damaged an important aspect of it, he said.
It was hard to know if someone had accidentally moved the stones or it had been vandalised on purpose, he said.
"Whether a sign would have stopped the vandalism is debatable but at least a sign would let people know what was here."
