Roscommon based Minister Denis Naughten is under pressure after revelations that he gave information to representatives of businessman Denis O'Brien about a takeover bid by INM.
Mr O'Brien is the largest shareholder in Independent News and Media, which tried to takeover the Celtic Media Group in 2016.
The Communications Minister informed someone working for INM that he planned to refer the bid to the Broadcasting Authority of Ireland for examination, two months before he made that information public.
The state's corporate watchdog has raised concerns that this being passed to Mr O'Brien is a case of insider information and a breach of stock market rules.
Taoiseach Leo Varadkar defended Minister Naughten in the Dáil this afternoon.