The deputy leader of Sinn Féin has claimed "household names" in the Progressive Democrats are among figures named in a dossier alleging tax evasion in politics.
It comes ahead of a meeting of the Public Accounts Committee, which was given the dossier.
The PAC has to decide whether to get legal advice on holding its own investigation or to hand the files over to the Gardaí.
Mary Lou McDonald says the claims of alleged tax evasion by civil servant Gerry Ryan are serious, and involve not only the PDs, but two other major parties.
"The allegations ... are very serious in respect of alleged tax evasion by named individuals – who are household names – from Fianna Fáil, Fine Gael, and the Progressive Democrats.
She also claimed the dossier says "that Mary Harney shut down his [Mr Ryan's] investigation when information emerged around these public figures".
Ms Harney shut down the investigation by Mr Ryan after seven years when she departed from the Department of Jobs. She was succeeded by Micheál Martin, who forwarded the report to gardaí.
Responding to Ms McDonald's remarks, the Taoiseach said that as a member of the Public Accounts Committee which will later meet to discuss the dossier, she was prejudging the contents of it with her remarks.
He also said that since he is not himself a member of PAC, he has not read the dossier or been briefed on its contents.