Frank Dunlop has told the Flood Tribunal he lobbied almost every member of Dublin County Council during preparations for Development Plans in the 1990s.
Mr Dunlop told the inquiry that it would be inconceivable for councillors not to have been aware of his role as a lobbyist for land owners and developers.
He said he approached almost every councillor and political party, even if he knew they would not support him.
He said he attended almost every special meeting of Dublin County Council between 1991 and 1993 while the development plan was being prepared.
He also described how he advised a Dublin businessman and land owner, Brian O' Halloran, on how to lobby councillors to get land re-zoned.
Mr O' Halloran's attempts in the early 1990s were unsuccessful but he later hired Frank Dunlop for £30,000 in 1997 to advise him.
Mr Dunlop said there were no discussions about payments to politicians but he did advise them about Christmas presents for councillors.
Mr Dunlop claims he gave Councillor Liam Cosgrave £2,000 in connection with this.
