© UnknownRobert Burnett shows the source of the smells near Edgars Creek in Coburg North
Friends of Edgars Creek environment group have raised the alarm over a "sewage" stench emitting from the permanently wet grassy slope on Moreland Council land near the former Kodak site.
Former president Stephen Northey said what was a small boggy patch two years ago had expanded into a 150m bog.
To date, its appearance and growth has baffled environmental and water authorities.
Moreland Council said tests by its officers, the EPA, Yarra Valley Water and Melbourne Water had failed to determine the cause.
But the EPA and Yarra Valley Water have ruled out leakage from sewage and water pipes under the site.
Yarra Valley Water spokeswoman Cheryl West said the matter appeared to be a drainage issue associated with the Kodak site and its dams.
Site owner Satterely's senior development manager Guy Williamson said he would send an excavator to the site in the next few days to see if there was an issue that they could solve.
The Council's city infrastructure director Nerina Di Lorenzo said it would retest the area.
''(We will) go over every possible reason why this would be happening.''
Why is so much water and mud being forced to Earth's surface in recent years? First it was Indonesia, then Azerbaijan and now Australia. Is there going to be a return to seeing Earth wallow in a primeval soup?