Irish Water Safety Chief Executive John Leech has urged divers to be well-trained and practised before undertaking dives in Irish seas.
He said the organisation is very concerned about the deaths of five divers in separate accidents in the past month.
A 57-year-old man was the latest person to die in a diving incident off the coast of Co Donegal at the weekend.
Rev Dr Stewart Jones of Donemana Presbyterian Church near Strabane, Co Tyrone, who was a qualified diving instructor, died after getting into difficulty near St John's Point lighthouse.
Speaking on RTÉ's Morning Ireland, Mr Leech said while many of those who died were experienced divers, conditions and decision-making can affect the outcome of any dive negatively.
He said physical fitness was also very important.
"Diving by its nature is not risk free - it's all a case of managing risk," Mr Leech said.
"Generally speaking, what we'd say is that planning a dive is so important, the whole stress-management, training is vital.
"The more training you do the less chance you have of dying, because the more time you put in in the water the more diving fit you are."