Fianna Fáil leader Micheál Martin is seeking a special debate in the Dáil on Tuesday over the Taoiseach's handling of John McNulty controversy.
Deputy Martin claims the Taoiseach's apology on Friday has not cleared up the matter.
The row surrounds Enda Kenny's decision to nominate the Donegal businessman for the Seanad by-election - and his appointment to the board of the Irish Museum of Modern Art.
Deputy Martin this evening called on the Taoiseach to give the Dáil a detailed explanation, outlining the entire sequence of events.