A NEW tuck shop for prisoners at the country's biggest jail will cost the taxpayer €75,000, the Irish Prison Service has said.

The shop, which will provide sweets, cigarettes, newspapers and other essentials for the inmates at Mountjoy Jail, is under construction as part of a refurbishment project at the Victorian jail in Dublin.

Mountjoy Prison is slated for demolition as part of a plan to build a new super prison on a greenfield site at Thornton Hall in north Co Dublin.

"The Irish Prison Service must maintain Mountjoy as a functioning prison until such time as Thornton Hall is open and improve conditions there where possible, as has been highlighted in Reports by the European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment, the Inspector of Prisons, the prison visiting committee and others," a spokesman said.

Overcrowding has been a continual source of problems for management at Mountjoy where prisoner numbers frequently exceed 600.

The prison's capacity is for 570 people but for two months last year, the jail housed between 660 and 680 people.

Other significant works also took place at the complex last year when a separation unit was opened at a cost of more than €350,000.

The latest improvement works are part of €3.55m worth of renovations currently underway in existing Irish prisons.

The upgrade of kitchens, an extension to visiting rooms, and commissioning of a new cell block at Wheatfield Prison is the most expensive project underway.

That work, which also includes the completion of a "fire safety contract", has been costed at around €2.19m, the Prison Service said.

Construction work on prison yards, roofs and a toilet block at Cork Prison is underway and is expected to cost €650,000.

Renovations at Limerick Prison are also underway where €560,000 will be spent refurbishing 14 currently unused female cells, visiting booths and a boiler.

A small extension of prisoners' locker rooms is planned at Castlerea Prison in Co Roscommon, and the cost there is estimated at €75,000.