The hill sits behind the port’s main terminal at Port Chalmers and has a history of slipping.
Two years ago, Port Otago undertook a $2million project to stabilise the hill by forming a series of terraces on its east and northeast faces.
Port Otago project manager Andy Pullar said the port was now installing a "catch fence" around the northern base of the hill to stop boulders falling on to the footpath and road.
The fence would be 4m above the road, 100m long and 4m high.
It would be held up by 13 posts anchored 10m into the ground. Each post would be supported by 1cum of concrete.
The fence would be able to catch rocks that were up to 1m in diameter.
"Occasionally boulders come down ... that was concerning and quite a risk to the public so this will take that away and make it a lot safer," he said.
A fence was considered the best of several options for stabilising the hill face.
Constructing the fence was "quite a process".
Contractors had been on site for more than a month already and were about halfway through drilling the anchors into the hill.
"Putting the fence up is the easy part. Drilling the anchors takes some time. We have to drill them right into the rock, so all the time goes into stuff you can’t actually see."
To lessen the likelihood of rocks being dislodged, Port Otago was also redirecting stormwater discharge and improving surface water drainage on the hill face.
The project was expected to be finished by the end of next month.
