The political opponents were among a group of up to 70 TDs and senators from all political parties who pledged their support for an inquiry into the murder of Co Roscommon priest Fr Niall Molloy following a society wedding in Clara, Co Offaly, in 1985.
Irish Independent journalist Gemma Doherty, who has conducted a two-year investigation into the murder, said she believes Justice Minister Alan Shatter must now order an inquiry.
"I feel the momentum is building now and it has to be dealt with," she said last night after addressing the all-party meeting at Leinster House.
The meeting was organised by Labour senators John Whelan and John Kelly.
"There is an urgent need for justice, accountability and transparency, as well as much needed closure for the two families involved, and indeed the community at large," they said.
The presentation heard allegations of a cover-up involving several bodies of the State and the Church following Fr Molloy's death on July 8, 1985, when he was found beaten to death in the mansion of his well-connected friends Therese and Richard Flynn following a wedding at their home.
"The priest had gone to the house requesting a large sum of money that was owed to him," Ms O'Doherty wrote in the Irish Independent. "His battered body was left bleeding on the floor for up to six hours before help was called. By then, it was too late.
Silence
"Instead, the local parish priest of Clara, Fr James Deignan, was called to the house. He subsequently said he did not know 999 was an emergency call, and had 'forgotten his glasses' so he could not read the phonebook to call a local doctor.
Shortly before dawn, he went to the local garda barracks and asked Sergeant Kevin Forde if the priest's death could be 'kept quiet'."
Although he refused to do such a thing, "a veil of silence fell over the truth," she wrote.
She added: "When the full facts are finally brought into the public domain, they will rock the foundations of the State."
Members of the Molloy family attending the presentation said
they were heartened by the renewed calls. "We would feel a little bit
more confident than before but we'll have to wait and see what comes of
today," said Fr Molloy's nephew, Bill Maher.