Cheaper insurance cover "will add to road deaths", according to Edward Shaw, chairman of the National Safety Council in the Irish Republic.
Shaw has been accused of "an outrageous attack" on young drivers, by suggesting any reduction in their insurance premiums would mean more deaths on the roads.
Shaw claimed the current high premiums acted as a deterrent and warned that reductions would put more young, inexperienced drivers on the roads and have "a disastrous impact" on the accident toll.
But he made clear that his criticism did not apply to the recent scheme of reduced cover offered by the Hibernian Group, as it included specific safety measures.
The Irish National Youth Council denounced Shaw's remarks as "outrageous", as did the Motor Insurance Justice Action Group (MIJAG), a young driver lobby campaigning for "a fair deal" for motorists under 25 years of age.
But there was strong support for his criticism from the Automobile Association (AA). Its spokesman for Ireland, Conor Faughnan, said some 55 drivers aged 17 to 24 were killed on Irish roads last year.
He added: "It is the cocktail of inexperience and confidence of young drivers that is so dangerous."
