Leading property website Myhome.ie has blocked access to bloggers who have been compiling lists recording the steep falls in house prices over the past year.
The website denied it was restricting information that might be of use to housebuyers and said it took the action last week to protect its good name and prevent breaches of the law.
"Anyone who is interested in buying a particular house will know already if the price has dropped," said 's chief executive Jim Miley.
A number of websites track house price changes, but until recently this was done manually. The process was then automated when unknown individuals devised web trawling software which searches through the main Irish property websites and identifies price changes over time.
However, last week Myhome, which is owned by Irish Times Ltd changed its format so that the names and prices of houses are now embedded in images.
This means they cannot be picked up by web trawling software; a side-effect is that they will not be picked up by Google searches.
The change creates difficulty for visually-impaired users, who rely on magnification of text to make websites more readable.
Mr Miley said Myhome would be in breach of its contract with housesellers if it allowed "spurious" data, which was often inaccurate, to be gathered.
The lists infringed Myhome's copyright and breached data protection laws, Mr Miley added, and they created confusion with the website's own reports on property trends.
These do not identify changes in the prices of individual houses but Mr Miley said future reports would provide more detailed information on local trends. The site is also to be redesigned to allow for individual house searches, he said, and the issue of access for the visually-impaired would be addressed at that point.
A spokesman for the Data Protection Commissioner said the use of people's addresses by third parties could involve breaches of data protection laws.
Another leading property website, Daft.ie, said it was "comfortable" with the web trawling software: "It's information in the public domain so we don't see why it should be hidden."
