The most senior civil servant at the Department of Justice could be called before a Dáil committee to explain why a letter about the Garda taping controversy was not seen by Minister Alan Shatter.
The chair of the Oireachtas Justice Committee has been asked to invite Brian Purcell to attend.
Former Commissioner Martin Callinan sent a letter on March 10, outlining how tapes and digital recordings had been made and kept at Garda stations since the 1980s, and confirming that the practice had been stopped last November.
However, Minister Shatter did not see the letter for a fortnight, which the Tánaiste described as "surprising".
The Transport Minister, Leo Varadkar, said the one with questions to answer is former Commissioner Martin Callinan.
"Rather than informing the Minister for justice at the time, as he should have done, he set up an internal committee within the gardaí and even made enquiries about destroying the tapes," he said.
He said opposition accusations against Alan Shatter was "old politics" and missing the real issue.
The terms of reference for the commission of investigation on the issue are expected to be discussed at tomorrow's Cabinet meeting.