The Government this morning agreed new arrangements for the transport and staff support for ministers in line with the terms of the Programme for Government.
Minister for Justice Alan Shatter has said the changes would produce substantial savings.
Under the new arrangements, garda drivers and State cars will be retained only for the President, the Taoiseach, the Tánaiste and the Minister for Justice and Equality for security reasons.
Ministers, together with the Ceann Comhairle and the Attorney General, will supply their own cars and civilian drivers will be hired, as has been the case for Ministers of State for some years.
Official cars and garda drivers will no longer be provided to former Taoisigh and former Presidents, except for important State occasions.
The new arrangements will come into effect for Ministers at the latest on 1 May, and in three month's time in the case of former Taoisigh and Presidents.
The Department of the Taoiseach said the moves will release a substantial number of gardaí to regular duties.
The decision does not affect the provision of a State car to the Chief Justice and the current Director of Public Prosecutions, the department said in a statement.
The Department of the Taoiseach said the measures will make a significant impact on the cost of Government, saying it reflected the determination of the Government to establish a momentum for political reform.
A Garda Representative Association spokesperson said it would be seeking clarification on the Government's plans before making any comment.
The Department said the moves would more than half the cost of transport for ministers and would lead to a reduction of 25% in the permitted staffing of Ministers' Offices and 33% for Minsters of State.
The new arrangements are in line with election pledges and follow a series of reviews.
Both Fine Gael and Labour pledged to tackle the cost of official transport in their election manifestos.
The bill for 27 cars and 54 garda drivers was nearly €11m over two years, according to the latest figures.
The Government has also announced a reduction in the maximum number of staff allowed in Ministers' private offices and constituency offices.
Minister for Public Expenditure and Reform Brendan Howlin said: 'The limits applied by the previous administration to the numbers of staff in Ministers' Offices are being reduced.
'This will result in the guideline numbers being reduced by four in total for each Minister and Minister of State.'