Sinn Fein representatives have been told to use personal information posted online by Facebook users to identify their home addresses.
An internal digital training seminar for party organisers shows they were told to "engage" with Facebook users to "elicit more specific information" which can then be used to "pinpoint them in the real-world".
In the presentation, Sinn Fein members were told "Facebook is KING" and instructed to use it as a means of identifying supporters they can "engage with in the real world".
The 16 page document said Facebook shows a person's name and "roughly where they live" but members were then told to get more information from users so they can "tag them as a social media engaged and follow up with a canvass on their doorstep".
They were told they can cross-reference information gleaned online with the party's electoral database, the Abu system, to find the home addresses of potential voters. Abu is a canvassing database developed by Sinn Fein which can rank individual voters based on their likelihood to vote for the party.
The 'Digital Media Training' presentation is dated September 2020 and party members were told to focus their efforts on Facebook rather than Twitter.
"It's the only social media platform that helps you build your base in your constituents, grow your support and get out the vote on election day," it said. "It provides extensive analytics on the people who are viewing and engaging with your posts including gender, age and location.
"It also has a highly sophisticated targeted advertising tool that is an essential element to reaching your voters as part of an effective digital market strategy."
The presentation said that the party's headquarters operation is "heavily engaged" in running Facebook ads to ensure their "messages get seen and heard" and encouraged TDs to also take out paid for advertising on the platform.
"Facebook allows you to run ads and micro-target and pinpoint them to very specific areas within your constituencies and to different audience within those areas," it said.
A Sinn Fein spokesperson said the only data their representatives hold "is information they are given by constituents".
"The party fully complies with Facebook's terms of service. We are also fully compliant with regulations concerning the use of the electoral register for exclusively electoral purposes."
The electoral register is made available for use to all elected representatives, he added.