LONDON — When the financial crash hit in 2008, it plunged Ireland into a crippling recession from which it has only recently stirred. But the toxic legacy of those years has not gone away, and now it has provoked another crisis, this time over media freedom.

A clash between one of Ireland’s richest and best-known businessmen, Denis O’Brien, and the national broadcasting company, RTE, has reopened wounds from the crash, raising questions about conflicts of interest at the top of Irish society, and about constraints on the country’s media.

At stake is whether journalists should report disputed allegations about some of the past financial dealings of Mr. O’Brien, a billionaire who amassed a fortune in the cellphone sector and has extensive media interests.

The issue peaked on Thursday when an Irish lawmaker, Catherine Murphy, made claims in the Irish Parliament, the Dail, about relations between Mr. O’Brien and a publicly run financial institution.