A file on former senator Ivor Callely has been sent to the Director of Public Prosecutions (DPP) after investigations into irregular mobile phone claims.
Mr Callely was accused of falsely claiming about €3,000 for mobile phone expenses for a company that had gone out of business and he faced a Garda inquiry as well as in-house probes.
He is accused of supplying invoices from the business even though it was not trading.
It is understood the DPP will be examining whether a fraud has been committed.
Last August former Green Party backbencher Paul Gogarty made an official Garda complaint over reports that Mr Callely allegedly used invoices from a company that had gone out of business to claim mobile phone allowances.
The Committee on Members' Interests of Seanad Eireann asked the Standards in Public Office Commission (Sipo) to examine the claims.
Sipo officials met earlier this month to examine a report on the inquiry.
"Having considered the report, the Standards Commission formed the opinion that Senator Callely may have committed an offence relating to the performance of his functions as a member," it said.
The controversial former Fianna Fáil senator was first suspended from the Seanad in July last year without pay for 20 days after he was found to have intentionally misrepresented where he lived for the purpose of claiming allowances, worth €81,000.
In January, Mr Callely won a High Court challenge over fines and the ban for the expenses scandal.
A parliamentary probe, by the Select Committee, found the scandal-hit Senator, whose political base was Clontarf, north Dublin, had deliberately misrepresented his normal place of residence as being his holiday home in Kilcrohane, west Cork, over three years.
A judge ruled the Seanad inquiry breached Mr Callely's constitutional right to justice and fair procedures as he was not given the opportunity to defend himself on the political ethics charges.
PA