A ''stupid'' social media hoax could have hampered the search for missing Owaka friends Sam Kopua and Lou Burling, Dunedin MarineSAR says.

A member of the public alerted police to an anonymous message on social media application Yik Yak, saying somebody's boat had capsized off Dunedin's coast last Wednesday.

Dunedin MarineSAR police adviser Martin Balch said searchers quickly established the claims were probably false, but they were close to assigning resources which could have proven useful in the search for Mr Kopua (77) and Mrs Burling (60) off the coast of Nugget Point.

The alert to the capsized boat off Taiaroa Head was reported to police about 5.05pm, while the search for the Owaka friends began at 6pm.

Advertisement

Police said the Catlins search was not affected by the likely hoax as it was ''initially attended by local staff and volunteers''.

Mr Balch said the ''boy who cried wolf'' hoax was frustrating for police and MarineSAR.

''When a call comes through to police, they are required to follow it through until it can be proved that it's not a problem,'' he said.

''When a genuine thing happens, it might be overlooked or missed or ignored.''

The proximity and timing of the calls also meant searchers had to be sure they were not related.

The anonymous Yik Yak poster had said he was ''surrounded by sharks, or words to that effect''.

Ships in the waters off Taiaroa Head were alerted, boat ramps checked and a unit sent to Harington Point to see if any capsized vessels could be seen.

The ''malicious'' hoax appeared to be the work of ''an idiot with too much time on his hands'', Mr Balch said.

Advertisement

A Southern district police spokesman said false reports were a waste of resources.

''Police and MarineSAR staff deployed a unit ... to take observations from a high point, ... messages were broadcast across the marine radio channel, boat ramps in the area were checked for empty boat trailers, and efforts were made to message the person back on Yik Yak for further information, all of which led staff to believe the message may have been a false report.

''Police have not received any further missing person reports for anyone in the area and no further information has been received to confirm this was a legitimate incident.''

Police would still like to speak to the person who posted the Yik Yak message.

Anyone with information about the anonymous post was asked to contact Dunedin police on 471-4800. Information can also be provided anonymously to Crimestoppers on 0800-555-111.