The alleged incident occurred on Saturday 15 August, near Manu Bay. The footage has since been removed from the Instagram account.
Ray Scrimgeour says DOC is now investigating. A man has come forward and is cooperating with DOC.
Tohorā and other marine mammals are protected under the Marine Mammals Protection Act. It is an offence to harass or disturb a marine mammal. Offences can carry penalties of up to six months in prison, a court-imposed fine of up to $250,000, or an infringement notice of up to $800.