A Fianna Fail TD said yesterday there was "nothing to hide" in relation to a development near Dublin Airport in which his brother was involved eight years ago.
Mr John McGuinness, from Kilkenny, accused Mr Liam Lawlor of taking "vindictive swipes in the dark" when he suggested that the development would be investigated by the Flood tribunal.
Speaking in the Dail on Tuesday evening, Mr Lawlor said he had no doubt that "in the fullness of time" Mr McGuinness would co-operate "very vigorously" with the tribunal
The project involved "a very major controversial rezoning out at Dublin Airport which was vigorously opposed by Aer Rianta but went through and is the basis of probably a major development today", he said.
Mr McGuinness said his brother, Michael, had developed an industrial site, for which planning permission was sought and granted "in a legitimate way".