Mr McWilliams said City Hall should be given the powers to impose hefty penalties on the owners of derelict properties.
“Say to landlords, ‘if you want to keep a place derelict, it’s going to cost you. There is going to be a site value tax. If you want to renovate, we are going to help you’ and so you encourage good behaviour and penalise bad behaviour,” said Mr McWilliams.
The economist said the cost of building houses is the same in Ireland as England, but sites are much more expensive here.
“That is why we should put a tax on dereliction to drive down the price of sites,” he said.
Mr McWilliams was the keynote speaker at the 14th annual Focus Ireland conference held at City Hall yesterday.