Key public sector workers such as nurses, teachers and gardai cannot afford to purchase the average house in four out of five of the State's main cities, according to a new report.
The survey, carried out by Halifax - the new name for the retail arm of Bank of Scotland (Ireland), found that earnings growth in these occupations continues to lag well behind house price growth.
Fire fighters, nurses and primary school teachers were also unable to afford the average house in Limerick in 2006, meaning all of Ireland's five largest cities were unaffordable for these occupations.
Halifax said the situation had deteriorated since 2003 when Dublin and Galway were the only unaffordable cities for all key workers.
Over the period March 2003 to March 2006, house prices in Ireland have risen by 43 per cent against an average increase in key worker salaries of 17 per cent.
The survey said nurses and fire fighters face were the worst affected of the various groups.
"Average house prices in Dublin are more than thirteen times the average salary of both a nurse and a fire fighter," it said.
Head of Retail and Intermediary at Halifax, Ian Corfield, said: "Unaffordability used to be confined to Dublin but increasingly it is an issue across the country."
Mr Corfield said: "While the Government does have some schemes to help first time buyers onto the property ladder, more needs to be done for key workers, who play a vital role in the economy, particularly in major cities."
"If this situation is to be resolved, lenders in Ireland need to team up with the Government to design funding schemes that will help these key public sector workers buy a home," he added.
Irish National Teachers' Organisation (INTO) general secretary John Carr said: "Without substantial pay increases there will be a chronic teacher shortage in city schools in a few years time".
Mr Carr said: "Many teachers, unable to afford houses in urban areas, are applying for jobs in rural Ireland."
"There is already a housing crisis for primary teachers. This is only being kept at bay by young teachers choosing to spend a few years in cities, after they finish training.
"As soon as they try and get into the housing market they find that the only way it can be done by moving to the country. So they apply for teaching jobs outside cities. This cannot continue indefinitely," he warned.