A sinkhole which could be up to 10m deep and is next to a popular walking track near Cromwell could be an old mining shaft.
The Central Otago District Council yesterday warned the public about the hole which is about 5m from the 45th Parallel Track.
The 45-minute walking track at the 45th parallel, up the side of the Sugarloaf near Lowburn, was developed by the Cromwell Rotary Club, which now maintains the trail.
It is on council-owned land.
Council parks team leader Ian Mann said Rotary had fenced off the sinkhole after it was discovered on Tuesday night.