It is one of several hoaxes broadcast on the maritime radio channel over the past week, and authorities are worried that those "crying wolf" may put others who are in real danger at risk.
Marine Search and Rescue adviser and Taieri Marine Radio operator Keith Simon said the most recent hoax call happened about 5pm yesterday.
"Maritime Radio kept asking for their location and the name of their vessel, but there was no answer.
"There was also one on Sunday.
"They called, saying there were six people on board a boat called Crumpy, and they wanted AOS [armed offenders squad] out there.
"They said some people fell out of the vessel and they were surrounded by sharks and they wanted police to shoot them.
"It was completely false."
A broadcast was also made on the Dunedin maritime radio channel about 7pm last Tuesday, claiming there was a boat in trouble, he said.
"We’ve had three on the marine distress channel and I believe they’ve also been affecting one of the police channels."
He was becoming increasingly angry with the behaviour because it could put someone’s life in danger, Mr Simon said.
"It’s time-wasting, but more worryingly, someone’s going to be in trouble one day and they’re not going to get the right response."
He believed it might be young people playing with a radio.
"It’s ridiculous and dangerous."
Senior Sergeant Anthony Bond, of Dunedin, said police were investigating the incidents and appealed to the public for information about the culprits.
"The maritime radio channel is for emergencies only, and it’s an offence under the Maritime Transport Act to transmit false or misleading messages," he said.
