The Mahon tribunal is to resume tomorrow with former Fianna Fáil press secretary and lobbyist Frank Dunlop scheduled to give evidence.
He was on the stand briefly before Christmas after taking a six-week break due to illness. Horse breeder Jim Bolger is also listed to appear before the tribunal tomorrow.
The tribunal had heard that Mr Dunlop bought a horse from Mr Bolger in March 1992 for almost £64,000. However he never saw the animal and it died the following year, after colliding with another horse.
Mr Bolger, based in Co Carlow, bred the horse from his own stock, the tribunal had been told, but it was never named or registered with the Turf Club.
When the story emerged at the tribunal last October, tribunal chairman Judge Alan Mahon said it was a "most peculiar transaction", it aroused a "very significant degree of suspicion" and "close questioning" of Mr Dunlop and Mr Bolger was warranted.
Other witnesses due to appear before the tribunal before the end of the month include Séamus Maguire, solicitor to Cork-based developer Owen O'Callaghan, former minister for agriculture Joe Walsh, former Dublin County Council planner Al Smith, publican Louis Fitzgerald and former Dublin City manager John Fitzgerald.
Broadcaster and journalist Eamon Dunphy is also to appear before the end of the month concerning contacts with Mr O'Callaghan in the 1990s.
Taoiseach Bertie Ahern is expected to give further evidence in February.
