A member of the public contacted the Otago Daily Times to say a truck last night spilled "thousands of litres of blood and guts" on the road, which then "ran down the gutters and into the stream".
Blood was "flowing down the gutters" and this morning the road remains closed.
Fire and Emergency New Zealand said they were called to the scene about 5:45 pm yesterday and determined the clean-up job to be "too large scale" for them.
Both the Dunedin City Council and the Otago Regional Council have been informed.
An ODT reporter at the scene late this morning said the road had been gritted but was still closed.