The Data Protection Commissioner says using facial recognition to track school attendance would be a “rather extreme” move.
The commission has released its 2020 report, showing it handled over 10,000 cases last year - an increase of 9% compared to 2019.
It contains a number of case studies, including a proposal by a Kilkenny secondary school to use facial recognition to monitor attendance.
The plan was scrapped amid data privacy concerns, and following a 'direct intervention' by the DPC.
Speaking on The Pat Kenny Show, Data Protection Commissioner Helen Dixon said it appeared the technology was not needed in this case.
She explained: "We jumped on it fairly quickly, because it seemed like a rather extreme implementation for a school - it was the first time we'd heard of a school rolling out a system like this.
"It seemed to be a case that they'd come across the technology, rather than really mapping out a problem that needed a certain solution.
"In the end, they didn't roll out the pilot, [after] we went through with them what was involved in terms of the processing of biometric data of students."
Ms Dixon children have special protections under GDPR in terms of personal data.
She said the school ultimately decided against the trial of the system as "it didn't seem like a necessary interference with the rights of the students".
The annual report adds: "The DPC considers that exposure to intrusive methods of surveillance without sufficient legal basis or justification can desensitise students at a young age to such technology and lead to them ceding their data protection rights in other contexts also."
Elsewhere in the report, the DPC explains how it engaged with Facebook over the firm's plans to use a tool to "help identify users at risk of suicide or self-harm".
If a risk was identified, Facebook would contact police or voluntary groups with the users' information.
Ms Dixon explained: "This is a service they have already rolled out in the US for a number of years, and they thought then they would roll it out in the EU.
"The concerns the Irish DPC had about it was that it was unclear what legal basis Facebook was using for the processing of what is very sensitive or special category personal data."
She said they engaged with Facebook, and it transpired the tech giant hadn't engaged with public health authorities about the plan.
She said the DPC ultimately deemed it 'prudent' that Facebook would work with those authorities before introducing the service in the EU.