Police have said that a hoax call to the Coastguard, which involved two lifeboats being unnecessarily deployed, could have put lives at risk.
The incident, at around 9am yesterday in Newcastle, Co Down, followed reports that a man had entered the sea after his dog had got into difficulty.
Both Newcastle RNLI inshore and all-weather lifeboats were launched in horrendous conditions. However, the search was stood down at 10.30am after the Coastguard declared it a hoax call.
Assistant Chief Constable Stephen Martin said: "The emergency services – whether it be the police, Fire Service, the Coastguard, the Ambulance Service – are there, especially on days like this, to protect life and when people carry out irresponsible actions like that they risk life."
The alleged incident took place approximately one mile north-east of Newcastle lifeboat station.
Both lifeboats had battled bad weather and rough seas to search for the man.
Also on scene were members of the Kilkeel and Newcastle shore-based Coastguard teams, and two helicopters from the Irish Coast Guard and the PSNI. Newcastle RNLI deputy launching authority captain Joseph McClelland said: "There was a heavy breaking surf in the area with a strong south-westerly wind blowing force seven and two metre swells.
"The lifeboats were on scene within minutes and the volunteer lifeboat crew searched in very challenging weather.
"We have since learned that the call for help was believed by the Coastguard to have been a callous hoax."
He added: "And, while we are relieved that no one is hurt, we are disappointed that anyone would call out the emergency services on a day like today, knowing it to be a hoax.
"They could have put people's lives at risk that were in real danger and diverted necessary search-and-rescue assets away from other work."