The Environment Protection Authority Victoria (EPA) was alerted by a member of the public after the Banyule Creek in Rosanna turned fluorescent blue yesterday.

The source of the discolouration has been traced to a dust suppressant used on the North East Link Project (NELP).

“NELP is cleaning up the drain, and EPA will monitor the project which will now assess how to ensure such incidents are not repeated,” an EPA spokesperson said.

“EPA investigations and assessments of any harm to the environment are continuing.”

Sandbags have been laid at the site in an attempt to reduce the flow of the coloured substance.

In a statement posted to the Banyule City Council website, the council said it was aware of the incident and was advised its drainage system was not the source of the pollution.

“The state’s pollution regulator, EPA Victoria, has been involved in leading the investigation and response,” the statement reads.

“Council will continue to work alongside EPA to inspect downstream areas and monitor for any ongoing effects.

“We’re committed to protecting our local environment and supporting the agencies managing this incident.”

The discolouration affects the creek south of Lower Plenty Road through Creekbend Reserve.

The North East Link Project has been contacted for comment.