Enda Kenny says he has full confidence in the head of Irish Water, John Tierney.
It comes as a Dáil committee prepares to call him for questioning over his role in the Poolbeg incinerator project.
The Taoiseach and others have backed the calls for Mr Tierney to take questions about his role in the project while he was Dublin's City Manager.
Our political correspondent Gavan Reilly reports: