A police spokesperson said they received the call about 3.35pm on Saturday but it did not specify a particular location.
Police had made inquiries and checked a range of boat ramps in the area, including Careys Bay, Back Beach, Portobello, Hoopers Inlet and Otago Peninsula, but had not found anything of note.
"We’re appealing to anyone who may have made the mayday call, who is now safe, to please get in touch with police to let us know", the spokesperson said.
At 5pm on Saturday, an Otago Southland Rescue Helicopter Trust chopper was seen flying over Cape Saunders.
In an update yesterday morning, a police spokesperson said they had located a boat on Blackhead Beach but it was unrelated to the mayday call.
— Police 105; Crime Stoppers on 0800 555-111, event P057889968.
