Up to 1,000 houses and apartments are likely to be built on the former Phoenix Park Racecourse as a result of Fingal County Council's decision last night to reject motions to preserve the 100-acre site as open space.
The rezoning majority on the council - mainly Fianna Fail and Fine Gael members voting en bloc - also rejected a motion from Labour and Green councillors calling for the decision to be deferred for consultations with the Taoiseach.
Mr Michael O'Donovan (Labour) referred to a recent letter from Mr Ahern to the Phoenix Park Racecourse Preservation Association, saying he was "making further inquiries" about its proposal that the site be bought for a city racecourse.
After the motion to defer was defeated by 14 votes to seven, Ms Pat Allison, the association's secretary, said Mr Ahern was "well aware" of the vote last night and she had been told he would be talking to the Fianna Fail councillors about it. She noted that they had all voted for the county manager's rezoning recommendation.
Mr Douglas Hyde, Fingal's chief planning officer, said the site was "particularly suitable" for housing as it was beside a rail link. However, 30 acres would be reserved as open space to provide a "visual break" between Castleknock and the city.
But Mr Joe Higgins TD (Socialist Party) said the entire site "should be left green and open" now the "monstrous proposal" for a casino had been abandoned.
Mr Sean Lyons (Ind) said London was now looking for space to build six racecourses within its M25 orbital motorway. The great advantage of the Phoenix Park Racecourse was that it was so close to the city centre that it used to be known as the "busmen's racecourse".
Mr David Healy (Greens) said it had been reported that the site had been sold to a firm of house builders for £37 million. If so, this was based on the presumption that it would be rezoned for housing and it was "depressing" that the planners were not prepared to protect it.
But Ms Sheila Terry (Ind) said the council could not forget that An Bord Pleanala had granted permission there for a casino, hotel and stadium. People in the area wanted "compatible" housing.
Mr Tom Morrissey (PD) said that even though the "dogs in the street" knew it was being proposed for rezoning as residential, he had not received a single objection. Mr Ned Ryan (FF) said people in the racing industry had been unable to "make a go of it".
The county manager, Mr William Soffe, said these were people "with racing in their blood" - a reference to Mr Robert Sangster and Mr John Magnier, who ran the racecourse in the 1980s. He believed the site was suitable for "high density housing in attractive surroundings".
Earlier, an attempt by Mr Higgins to reverse a 1993 decision by the council to rezone 79 acres of land at Laraghcon, on high ground above Lucan village, was defeated 13 to eight after Mr Soffe warned it would leave the council open to a massive compensation claim.