The only road linking Milford Sound with Te Anau and Central Otago will soon be open again around the clock.
Fiordland's Homer Tunnel has been closed to traffic every night since mid-December because of the danger of rock falls.
The scenic Milford Rd is a vital one for the tourism industry, being the only way vehicles can get in or out of Fiordland. But for the last month the route's been off limits at night, forcing tourists to head home early.
“There's only the airport and ship travel apart from the Milford Rd,” says NZTA Southland area manager Peter Robinson. “It's the only access into Milford.”
A series of rock falls above the west portal of the Homer Tunnel meant it had to be closed between 7pm and 7am, after rocks as big as cars hit the road.
“We've restricted the hours of operation so that we can have spotters looking for when those rocks do come down, so we can manage the traffic to avoid them being there when the rocks come down,” says Mr Robinson.
Now a series of giant steel cages are being installed on the Milford side of the tunnel, lined with strong steel mesh designed for rock fall protection.
The 60-metre long portal extension will mean the Homer Tunnel can stay open 24/7. It'll also let the NZTA carry out safety work, using a helicopter with chains underneath to clear unstable rocks from the tunnel's entrance.
But the emergency project isn't a permanent solution.
“In terms of long term, there could be a concrete extension to the existing portal, or we may have to do rock work above,” says Mr Robinson. “There are a lot of techniques now for stabilising loose rock.”
The road's long been a challenging one for the NZTA. An avalanche programme each winter includes controlled blasting of snow before it becomes a hazard.
But even the steel cages would crumble under the weight of an avalanche, meaning they'll be taken away before the winter season begins.