Legislation aimed at improving water safety is said to be having a negative impact on several lifeboat stations and on sail training schools.
Implementation of the legislation, which was introduced after the Pisces angling boat sank in 2002, is understood to be causing difficulties within some Royal National Lifeboat Institution (RNLI) stations.
Lifeboats cannot now carry Garda or Irish Coast Guard personnel on searches unless they have approved "passenger boat" certification.
The Irish Sailing Association (ISA) has also said that the imposition of the passenger regulations on sailing schools could have a detrimental effect on training and certification programmes run under its auspices.
The Merchant Shipping (Passenger Boat) Regulations 2002 were initiated by former marine minister Dermot Ahern after the outcry over the loss of five lives in the Pisces angling boat incident off Fethard-on-Sea, Co Wexford, in July, 2002.
The subsequent investigation noted that unlicensed vessels should not be used for carriage of passengers, and recommended a series of measures relating to the existing Merchant Shipping Act.
However, application of the revised regulations to sail training schools and lack of definition in relation to wording has caused concern within the RNLI, and the ISA, which says training schools with excellent track records could face immediate closure due to the cost factor.
RNLI vessels exceed safety standards for passenger boats, but the additional certification required would represent an extra burden on an organisation which relies largely on voluntary contributions and voluntary crew. It now means it cannot carry anyone, apart from rescued casualties or RNLI personnel - which affects both searches and fundraising events where members of the public are invited to visit craft.
Mr John Roberts, RNLI operations manager at Clifden lifeboat station, said that he had been confronted with a dilemma on two occasions over the past two years as a consequence. During last year's search for a missing bather off Renvyle House Hotel in Connemara, five or six islands needed to be covered in case the swimmer had sought shelter and was suffering from exposure.
The Cleggan Coast Guard unit, which has no vessel, had about 15 personnel on shore to help, but the lifeboat couldn't transport them to search the islands.
In a separate incident where two bathers were drowned off Aerfort beach, Co Galway, the father of one of the two asked Clifden lifeboat if he could be taken to the spot where his daughter's body was found. He wished to say a few words and put some flowers on the water, Mr Roberts recalled.
However, the lifeboat wasn't allowed to take him, so Mr Roberts took him in his own inshore vessel.
The ISA says it is committed to marine safety, but believes that when the legislation was originally drafted it was not planned to apply it to over 1,000 sailing dinghies, open keelboats, open powerboats and inland motor cruisers attached to sailing schools which aim to train for marine safety.
Marine tourism is also being affected, as overseas certification is not deemed acceptable, and internationally accepted safety equipment is not being recognised, it says.
The Department of Transport had no response on the issue when contacted by The Irish Times.