Sinn Féin leader, Mary Lou McDonald, has said an issue relating to now-resigned Sinn Féin TD (MP) Brian Stanley has been passed on to An Garda Síochána (Irish police).
Stanley resigned from the party on Saturday.
Stanley said his decision follows on from a complaint that saw him brought before an “internal party inquiry”.
McDonald said an internal process was carried out after a complaint against Stanley was made at the end of July.
In a statement, the Laois TD described the inquiry process as “seriously flawed”.
Stanley said the way Sinn Féin has “dealt with this and other matters across the wider party in recent months, I can no longer have confidence in it”.
In a statement McDonald said during the early stages of an internal investigation “further information was brought forward which resulted in a counter allegation being made”.
The internal process has now been suspended and information passed on to An Garda Síochána (Irish police).
“These are not outcomes that anyone likes to see but let me be clear we have robust procedures for dealing with these issues and they will be followed at all times and apply equally to all members of the party,” she added.
First elected to the Dáil (lower house of parliament) in 2011, Stanley has been involved with Sinn Féin for 40 years and is the chairman of the Committee of Public Accounts.
Stanley said he would continue working as an “independent republican TD” outside the party.
Earlier this week, Kildare-South TD Patricia Ryan resigned from Sinn Féin, also citing unhappiness with the party.
It follows controversy for Sinn Féin in recent weeks, including criticism for how the party dealt with the case of two press officers who resigned after giving references for a former colleague who was being investigated for child sex offences.
Sinn Féin has been approached for comment.