The Milford road from the Homer Tunnel to Milford Sound is officially open 24/7 again.
The road has been closed at night for several months because of rock fall risk at the western entrance of the tunnel.
NZ Transport Agency Southland area manager Peter Robinson said snow and ice had "locked up" the faces of the rock and debris field above the western entrance to the tunnel.
This including the site where a 2000-tonne section of unstable rock was removed in June.
High-magnitude blasts, like the one used in June, usually caused rock behind the blast zone to "relax" and was likely to create some more loose debris over time, he said.
That debris was expected to be removed over the spring and summer, once the weather improved, he said.
Until that work was done, the temporary portal extension at the tunnel would remain.
The work would be done in a way that minimised disruption, he said. The agency would speak with Milford Sound business operators to discuss timing.
- The Southland Times
Should April Miller be allowed to play in the presidents grade rugby competition?Related story: Southland woman banned from men's rugby side
Subscribe to a digital replica of The Southland Times.
Southland Times subscriber news and information.
Click here for information about advertising with The Southland Times.