345,000 homes and apartments in Ireland are currently vacant, according to new research from University College Dublin. The figure represents 17% of all housing stock in the country.

The report says that the National Asset Management Agency could delay the normal market recovery process by seeking to prevent downward price corrections.

Stripping out holiday homes, dereliction and factors in normal vacancy levels to facilitate the rental market, the UCD study finds the country still has 170,000 houses and apartments it does not need.

More than one in five homes outside the greater Dublin area are empty, compared to around one in 12 in and around the capital.

In a market so blighted by oversupply, the report finds house prices are still at very high multiples of average incomes. Sellers, the report finds, are unwilling to face the inevitable and reduce prices.

The report says market interventions like NAMA, which attempt to prevent downward price corrections, often delay rather than prevent normal market recovery.

It says Government policy aimed at maintaining price levels with so much over supply could prove both ineffectual and wasteful.

It says house prices continue to remain at very high multiples of average incomes and lenders are tightening up on what they will loan out and to whom they will lend the money.

Meanwhile, the Construction Federation has said there in a need for accurate, reliable data on housing stock levels.

The CIF acknowledges that the figures in today's study are high but said different studies have come back with a variety of figures. Its own figures suggest that 35,000-40,000 new homes remain unsold.

It believes the problem of unsold housing will resolve itself in around nine months in Dublin. With no development in the pipeline, waiting lists for housing will result in high growth areas.

The CIF admitted there is a problem in many counties around the country but said the market will ultimately sort that out.

Hubert Fitzpatrick denied that developers built too many houses at the height of the boom. 'Developers built to the demand that existed at the time,' he stated.