MORE than €168m worth of properties were purchased by the state at the height of the boom, with all thought to have lost at least a third of their value.

The expenditure was overseen by the Office of Public Works (OPW), which picked up the tab for the costly purchases, many of which relate to the doomed decentralisation projects.

Of those properties, €33.6m worth of sites and other buildings are currently lying vacant with no clear plan for their future use.

All 10 of them were bought at highly inflated prices, with several of these likely to have lost at least 50% of their value, according to estate agents.

The most expensive purchase of all was the €41.8m paid to UCD for lands at the National Concert Hall site in Dublin city centre.

The concert hall is due to be the subject of a major redevelopment project, which has been prioritised by arts minister Mary Hanafin.

Another significant buy involved the purchase of the former FAI headquarters on Merrion Square in the centre of Dublin for €19.95m – well in excess of its current market value. It is being used as government offices, according to the OPW.

Of the sites that remain vacant, the most costly was the €10.075m paid for a number of plots of land in Drogheda, Co Louth. They were bought in October 2007 for decentralisation purposes but the government decision to stall that project has left the site in limbo.

One local estate agent – who did not wish to be named – said: "These are the types of properties that would be going into Nama if the owner was not the state.

"Spending €10m on sites in Drogheda may have seemed like good business at the time but they are worth a fraction of that now."

The OPW also bought another property in the Co Louth town six months earlier, for which it paid €2.325m – it also remains unused.

Another costly purchase in 2008 was €8m for a site in Waterford on behalf of the Department of the Environment. It has lain idle ever since. Other expensive buys were a €2.1m site in Dungarvan, Co Waterford, and a €2.9m land deal in Cavan.

Both properties were bought within two months of each other in 2006 but have remained vacant for more than four years.

Other deals made at the height of the boom include a €1.5m-site in Edenderry, Co Offaly, in February 2007, a €1.465m site in Tipperary in January 2007, and a €2.5m plot of land in Claremorris, Co Mayo, in January 2007.

The mad dash for property continued right into 2008 when yet another site for decentralisation was bought for €1.8m, in Thomastown, Co Kilkenny.

The OPW said a site purchased on the North Circular Road in Dublin for €23.5m had been put to use by the Prison Service. It was bought as part of an ambitious plan for an urban redevelopment of the area around Mountjoy Prison on the basis that the jail was to be closed.

Other expensive properties were a €5.17m warehouse in Damastown in Dublin 15 and a €7.4m office in Tullamore, Co Offaly.