Opposition parties have accused the Garda Commissioner, Mr Pat Byrne, of "hypocrisy" after he claimed that gardaí driving Government members could break the speed limit at their own discretion.
Mr Byrne's comment, in a letter to the National Safety Council, followed a spate of speeding incidents involving the car used by the Taoiseach, Mr Ahern, and those of other Cabinet members.
Released under the Freedom of Information Act, the letter stated that while Garda drivers were obliged to set an example to other drivers, they must also be allowed decide themselves when to break the speed limit.
This led Labour's transport spokeswoman, Ms Roisin Shorthall, to claim Mr Byrne was displaying "contempt" for road safety.
Ms Shorthall said: "The Garda Commissioner has made absolutely no distinction between the circumstances in which it may be necessary to exceed the limit and those incidents we have had in recent times of Ministers breaking the laws we must all abide by in order to get to football matches, or to drop their families home.
". . .It is one thing to legislate for exceptional circumstances where it may be necessary to speed, but it is quite different when you fail to condemn the utter contempt that has been previously displayed for unnecessarily jeopardising the safety of other road users."
The Green Party also criticised Mr Byrne, who said in his letter that decisions about when gardaí might break the speed limit "must be left to the discretion" of individual drivers. The party's transport spokesman, Mr Eamon Ryan, said Mr Ahern was saying "do as I say, not as I do" in relation to road safety.
He added: "Ministerial drivers are well qualified. However, no amount of training can prepare them for an unexpected event on our roads. Then their 100 miles per hour speed will render them powerless to react and avoid catastrophe for themselves or some other unfortunate road user."
