Justice: Labour justice spokesman Joe Costello has called for an independent inquiry into the circumstances surrounding the purchase of the 150-acre site in north Dublin at a cost of €30 million earlier this year for a new prison to replace Mountjoy.
Mr Costello said he had also passed on various documentation in his possession on the purchase of the site, which cost eight times the normal price of agricultural land.
Describing the deal on the farm at Thornton Hall, south of Ashbourne, as a last minute arrangement, he said that the objective criteria that were to be used were "totally jettisoned when the final decision was made".
"I'm calling on the Taoiseach to appoint an independent person with knowledge of the procurement practices within the civil service to conduct an inquiry into all the circumstances throughout the purchase of Thornton Hall."
He also accused the Government of failing to deliver on its promise of 2,000 extra gardaí and called for an urgent review of immigration policy, which he described as "a shambles".
Meanwhile, in a special address to conference, Frank McBrearty jnr, whose false arrest for murder is at the centre of investigations by the Morris tribunal, said he blamed the Minister for Justice on his family's current situation.
The McBreartys have withdrawn co-operation from the tribunal over the refusal by the Government to underwrite the family's legal costs.
Mr McDowell has said such a guarantee was not something the Government could make to anybody, and that costs were an issue to be decided by the tribunal itself.