Between 100 and 150 litres of sewage has leaked on to public land behind a commercial portaloo facility in Avondale.
A witness at the scene said it looked like there has been a "poo tsunami".
The man said sewage had spilt on to an area of grass between the back of a portaloo business and the northwestern cycleway.
"There's s**t on the grass stretching about 100m from the back of a business where a bunch of port-a-loos are stacked," he said.
![Clean up from a sewage leak on to public land behind an commercial port-a-loo facility in Avondale. Photo / Jason Oxenham](https://www.nzherald.co.nz/resizer/v2/RIXCMCL5HJ4U7RGR3SAUI4W73I.jpg?auth=249054fe72f0c95ed7669dceea91489b28a2fa7c37fd89083a25248d8d8fd8f0&width=16&height=11&quality=70&smart=true)