The Department of Conservation is investigating concerns over a jet ski driving through a pod of dolphins after a video of the incident emerged on Instagram.
The video, which was posted on Instagram by Auckland real estate mogul Ricky Cave on Sunday, shows a jet ski travelling around 22km/h as dolphins swim around it.
A member of the public contacted DoC and the Herald raising concerns about the Cave's actions and the safety of the dolphins after seeing the video online.
The video was taken out from Pauanui in the Coromandel at the weekend, according to a source.
DoC investigations team leader John Wallwork said the video had been passed on to its compliance team for further investigation and to determine whether the behaviour was in breach of the regulations.
"We'll be determining the next steps after we do some more work on this one. DoC follows up on all information and tip-offs provided by the public."
A breach of the Marine Mammals Protection Regulations can incur a penalty of between $400 and $600. More serious incidents can be prosecuted through the courts.
DoC's advice for how boaties, jet skiers and other people enjoying the water and coastlines around New Zealand should behave near marine mammals is available online and recommends vessels travel no faster than idle or "no wake" speed within 300m of marine mammals such as whales, dolphins or seals.
They should approach from a direction that is parallel and slightly to the rear and should not circle the marine mammals, obstruct their path or cut through any groups. The vessel should also slowly idle away.
With dolphins in particular, the skipper can gradually increase speed to outdistance dolphins but it should not exceed 10 knots (18km/h) until they are more than 300m away.
Cave did not respond to requests for comment.