The Communicorp media company has said no Irish Times journalists will be allowed as contributors on any of its radio stations until further notice.
In a statement this evening the company said it had taken the decision following an article written by Fintan O'Toole published on 12 September.
Communicorp said it had asked for an apology from the Irish Times for the article but the newspaper had refused.
Irish Times Editor Paul O'Neill has said there were no grounds for such an apology or for a retraction of the piece, which it said the media company had also sought.
He said Mr O'Toole was entitled to express his opinion and that the Irish Times was entitled to publish it.
The article in question was a column by Mr O'Toole in relation to the controversy over comments made by broadcaster George Hook on Newstalk.
Mr O'Neill said the Irish Times had also carried an article by Newstalk Managing Editor Patricia Monaghan on 16 September in which she was given an opportunity to respond to Mr O'Toole's column.
Mr O'Neill said Ms Monaghan's article fully reflected the views of Newstalk staff.
He said it was a matter for Communicorp to decide who participated in its programmes.
Mr O'Neill said equally the Irish Times reserved the right to publish a wide range of opinion without fear or favour and would continue to do so.