The Rob Roy track in the West Matukituki Valley was closed in July 2019 after a significant slip undercut the track, making it unsafe to access.
Prolonged rain in December 2019 and February 2020 had caused further damage to the track.
Doc community ranger Nicole Sutton said the track’s remote location had made the repairs challenging.
Doc staff and contractors had been working hard over the past month to reroute about 450m of damaged track but the new alignment was through native bush and outside the identified rockfall and landslip zones, she said.
Before the Covid crisis an estimated 20,000 people visited the Rob Roy Glacier each year.
The 10km return easy graded walk goes through dramatic alpine landscape that includes snowfields, glaciers, sheer rock cliffs and waterfalls.
"This summer is a great time to explore our backyard and we want everyone to have safe and enjoyable experiences,” she said.