Earlier this week, the structure was erected along the N15, close to the N12 junction in Eschdorf, due to fears of landslides.
The Roads and Bridges Authority said that a large rock had come away from the embankment along the side of the road, necessitating repairs. The barrier would be in place for at least another week while the issue is addressed.
A spokesperson confirmed there was currently no danger to motorists at the location. The barrier is to be removed once the work has been completed, allowing all lanes to reopen as normal.
