The track on Oamaru's Cape Wanbrow is popular for viewing yellow-eyed penguins and is used by 40,000 visitors a year.
The new tourist season is just starting and the Department of Conservation has now had the track cleared of debris.
A wooden retaining wall is being built at a cost of about $10,000 to protect 120m of the track from further slips.
About three-quarters of the track was damaged by slips, and a digger worked for about two days last week removing them, so the track could be reopened.
Doc ranger Kevin Pearce said yesterday every care had been taken to ensure the welfare of nesting birds in the area.
The department faced a difficult choice over reopening the track during the nesting season.
It had to allow time for the track to dry out and slips to stop moving before a digger could get into the area.
Leaving the track closed until after the nesting season would have affected visitors, who might have ignored the closure and placed themselves in danger.
"With the onset of the tourist season, a decision had to be made to reopen the track," he said.
