Visitors are littering the Milford Track with toilet paper and human waste.
A Department of Conservation (DoC) contractor told Radio New Zealand the amount of human waste visible was "disgusting" and that the situation was getting out of control.
"On some of the Great Walk tracks, you find poos and toilet paper just littered down the side of the tracks," the contractor told Radio New Zealand.
"In some of the campsites along the Milford Road, it's really quite bad, you've only got to walk 20m into the bush and it's all over the place."
The contractor said the Milford Track was getting busier each year, and that many tourists did not understand how to use a toilet.