Strict rules on the use of State cars have been called for, following the revelation that it costs about €170,000 per year to provide each Cabinet minister with a State car.
The figures arose after the Sinn Féin TD, Mr Seán Crowe, sought the information in a parliamentary question.
The Minister for Justice, Mr McDowell, said it cost €2.9 million annually to provide cars to the Cabinet ministers. This included the provision of a Garda driver and the running of the car.
Mr Crowe said the figure was "staggering and impossible to justify". He said he recognised the need for the 15 Cabinet ministers to have access to drivers and cars, but there must be restrictions on the use of the cars.
It was "disgraceful" that some ministers flew to a location, while their cars drove there to meet them on arrival to take them to the venue, he said.
"We have to ask if ministers are doing party political work, constituency business, or ministerial work. As a taxpayer, I object to paying for frivolous trips."
A spokesman in the Garda Press Office said there were no rules outlining where a minister could or could not take a car. "The car is there primarily to protect the minister," he said. "The driver is under instruction to take the minister wherever he or she wants to go."
The Tánaiste, Ms Harney, was embroiled in controversy last year when it emerged that she had been flown to Sligo Airport in an Aer Corps aircraft while her driver travelled separately to collect her from the airport and take her to Manorhamilton in Co Leitrim to open an off-licence.
Meanwhile, the Department of Foreign Affairs is still involved in negotiations to acquire hundreds of luxury cars to transport dignitaries during next year's six-month EU presidency.
Last month it emerged that the Department was considering several options, including hiring or buying cars as well as having cars sponsored.
Thousands of delegates will begin arriving here from January to attend more than 100 meetings around the State.
