Police are investigating reports of contamination in a Canterbury river.
Officers are looking into how prills of DDT and arsenic came to be in a small area of the Opuha River, near the Skipton bridge.
"We are working closely with ECAN [regional council Environment Canterbury], who reported the incident to police on 9 October," Acting Detective Senior Sergeant Richard Quested said.
"The police investigation is at a very early stage and we are keen to hear from anyone that has any information relating to this matter.
"Police would like to reassure the public that they are working with ECAN and other agencies to ensure the risk to the public is minimised."
