Environment Southland has launched an investigation after sewage from a blocked pipe flowed into the Riverton Estuary on Wednesday. 

The regional council recommends people and animals avoid contact with the water in the estuary for the next few days, after the spill close to the Riverton-Tuatapere Highway. 

The spill has been stopped and work has been carried out to clean the surrounding area. 

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ES could not confirm how much sewage spilled into the estuary, when it was reported, or when the spill was stopped.

"We always undertake a full investigation for incidents and we can’t make any further comment while that is ongoing," communications coordinator Tania McCann says. 

ES did say, however, that it "appears a blocked pipe caused the issue, rather than a cracked or broken pipe".