I know for a fact that Dublin in particular has been plagued by 'land barons' They buy as much land and property as possible in Dublin city, and then just leave it sit there. This lowers the supply of space in the city thus increasing the value of all their land, which enables them to get loans to buy even more land.

I know a councillor who worked on a report which predicted, in the 70's, that because of Irish property laws it was possible that this could be happen, and the laws should be reformed. The laws were never reformed and it happened.

https://issuu.com/conormccabe/docs/1974kennyreport