High levels of e-coli bacteria were found in Lake Wakatipu after a sewage spill at Kelvin Heights in October.
A report to the Queenstown Lakes District Council's utilities committee by 3 waters manager Gerry Essenberg said samples taken from the lake 50m each side of the spill returned high bacteria counts.
However, there was no risk to public health, he said.
The spill occurred after a contractor working on the upgrade of the Kelvin Heights track broke the 200mm sewer main by pushing a rock through the pipe wall on October 27.
The sewage spilled into the lake downstream from the Kelvin Heights water intake so did not affect public health, he said.
The section of pipe was replaced within six hours.
