The Department of Conservation is trying to track down a group of people who were on board two speedboats that were driven through a pod of dolphins north of Auckland.
DOC says the incident was filmed by a drone operator who has supplied a video of the incident at Army Bay on the Whangapaora Peninsula to the department.
It shows a boat speeding through a pod of dolphins several times and the terrified marine mammals diving to try and escape.
DOC Auckland Marine Ranger Dr Krista Hupman is reminding all vessel operators that they must adhere to the conditions governing behaviour around marine mammals as listed in the Marine Mammals Protection Regulations.
That is, all boaties must ensure they travel no faster than 10 knots within 300 metres of any dolphins, whales, seals and sea lions.
"In addition vessels must only approach whales and dolphins from behind and to the side, and must not obstruct the animals' path or cut through any group," Dr Hupman said.
DOC is calling for public help with its investigation into the incident which was filmed on September 10.
"We want to talk to the people who drove the speedboats through the dolphins," Dr Hupman said.
Anyone who notices a marine mammal being harassed is also urged to contact DOC immediately.