The party has written to Ceann Comhairle Seán Ó Fearghaíl claiming that if the Fianna Fáil motion is allowed proceed it would be setting a “worrying precedent”.
The parties have both put down motions in response to the scandals in the gardaí, including the almost 1m breath tests that were falsely recorded by members of the force and the near 15,000 wrongful traffic convictions.
Both motions are likely to increase the pressure on Ms O’Sullivan who is today expected to come in for more criticism from members of the force when she attends the annual conference of the Association of Garda Sergeants and Inspectors.
The Fianna Fáil motion, which will be debated in the Dáil tonight, calls for more power to be given to the Policing Authority and an overarching review of the management, but stops short of calling for Ms O’Sullivan to step aside.
While Fianna Fáil does not have confidence in the Garda commissioner, it claims the Dáil does not have the authority to remove her.
Labour is expected to support this motion but will table its own amendment calling for Ms O’Sullivan to resign.
Cabinet is also likely to discuss the Government’s own amendments to the motion when it meets today.
While Fianna Fáil only submitted its report last Friday and has put another motion around mental health on the long finger to make room for it, the Sinn Féin motion was put forward a number of weeks ago.
The Dáil schedule means the Sinn Féin proposals will not come before the House until tomorrow .
Writing to Mr Ó Fearghaíl, Sinn Féin’s Aengus Ó Snodaigh last night said he wishes “to object in the strongest possible terms to the Fianna Fáil justice motion”. He said “its purpose was to gazump the Sinn Féin motion on the same topic which has been on the order paper for over two weeks”.
Motions can be rejected if they are found to be contrary to standing orders which state that motions should not include repetition or anticipate the discussion of any subject of which notice has been given.
However, it is understood that the go-ahead was given for both motions as it was deemed that they were different enough not to infringe this rule.
Calling for a withdrawal of the Fianna Fáil motion Mr Ó Snodaigh said that “anybody reading both motions can see that the subject matters are the same”.
“I believe that if allowed proceed [it] would be setting a worrying precedent. In the past, standing order 58 has been quoted at my party when we have submitted motions and they have been blocked accordingly,” Mr Ó Snodaigh wrote.