The lobbyist Frank Dunlop is expected to tell the Mahon tribunal that he paid three members of Dublin County Council in the 1990s for their support in relation to lands at Dundrum in south Dublin.
The tribunal will this week begin a new investigation into the former Pye lands in Dundrum. It is understood that Mr Dunlop will tell the tribunal that he received about €5,000 for this particular project.
He will say that he gave £1,000 to Don Lydon and Tony Fox of Fianna Fáil. He is also expected to say that he paid the late Fine Gael councillor Tom Hand £2,000 for his support.
The new module of investigation into the Pye lands is to get under way on Wednesday.
Mr Dunlop is scheduled to appear next week.
Among those also listed to give evidence in the new module of investigation is the former Assistant Dublin City and County Manager George Redmond.
The tribunal will resume tomorrow after its Christmas break with evidence from the former chief Fianna Fáil fundraiser Des Richardson, in relation to an investigation into land at Cloghran near Dublin airport.
A businessman who was part of the consortium which owned the land has said that it paid nearly £10,000 to the advertising agency Saatchi and Saatchi on behalf of Fianna Fáil in 1993 in a so-called "pick-me-up" payment.
In evidence before Christmas, Mr Richardson told the tribunal that almost 5 per cent of donations to Fianna Fáil came through "pick-me-up" payments.
These involved donors agreeing to pay bills owed by a political party rather than making a contribution in the conventional way.
"Pick-me-up" payments allowed donors to give money confidentially to a political party.
Mr Richardson said that there was nothing underhand in this form of donation.
However, he said that if they made a donation in this way they could not claim back VAT.