The Minister for Justice, Mr McDowell, plans immediately to seek the formal approval of Cabinet to demolish Mountjoy Prison, Dublin, and build a replacement facility on the outskirts of the city.
Mr McDowell has indicated his preference for the demolition of Mountjoy but it was never believed the matter would be given immediate attention.
However, last night he said that although no site has yet been identified for the new jail, he will seek Cabinet approval for his plans in the "next week or so".
News that Mountjoy's closure is to be considered so soon is likely to further anger prison officers. They have strongly criticised cost-cutting moves by the Government to close two prisons and place the running of two minimum-security facilities outside the remit of the prison service.