The Oireachtas Committee on Foreign Affairs is to ask Katherine Zappone to speak about her appointment as an UN special envoy last July.
The former Minister for Children later declined the role following political uproar.
Last week, Minister for Foreign Affairs Simon Coveney apologised to the committee over what he described as the "political fiasco" surrounding the appointment of Ms Zappone to a UN role.
Ms Zappone, who lives in the US, cannot be compelled to appear before the committee, which is also seeking to hear from the Secretary General at the Department of the Taoiseach, Martin Fraser.
Mr Fraser was sent a memo from the Department of Foreign Affairs, with details of Ms Zappone's proposed appointment, after 9pm on the night before the Cabinet meeting of 28 July.
Later today, the Dáil will debate and vote on a confidence motion in Minister Coveney.
Sinn Féin is due to move its no-confidence motion against Mr Coveney at around 6pm, over what it says is a lack of transparency around Ms Zappone's appointment.