The Data Protection Commissioner (DPC) has recommended that Sinn Féin tell voters about its Abú database with a notice on all canvassing and electioneering literature.
In a report published today, the commissioner said this should continue as long as the Abú database continues to exist.
Today's publication follows on from articles in the Irish Independent earlier this year regarding the alleged storing of personal information of voters on an internal party database by Sinn Féin.
The DPC then decided to carry out data protection audits of all political parties' processing of voters' personal data.
In relation to Sinn Féin, it found that the sample canvassing literature made no reference to the Abú database or to the fact that canvassing information may be processed on that database.
The auditing officers found the total number of eligible voters marked on their political opinions on the Abú system was 5.85% of the overall number of voters on the database.
Seven political parties were found to have conducted market research or opinion polling using their own members, supporters, or activists.
The DPC was satisfied that no personal data was processed during those activities by the political parties concerned.
Political parties that process personal data revealing political opinions of over 30,000 voters should now appoint data protection officers.
This means Fianna Fáil and Sinn Féin are now required to have protection officers and both have done so.
Fianna Fáil, Fine Gael and the Green Party were told to update their privacy policies to take account of their use of electoral registers.
Fine Gael Senator John Cummins called on Sinn Féin to "decommission" its Abú database following the publication of the DPC report.
"More than 203,000 voters had their voting intentions listed inside this secret system. That is the equivalent the population of Cork city," he said.
However, Sinn Féin spokesperson on Housing, Local Government and Heritage Eoin Ó Broin said his party had engaged closely with the Office of the Data Protection Commissioner throughout the audit, and is in the process of implementing all recommendations.
"We welcome the finding by the Data Protection Commissioner confirming Sinn Féin's use of electoral registers for electoral purposes. This has been a useful exercise in safeguarding the democratic process," he said.
Additional reporting: Mícheál Lehane
