27 close contacts are now self-isolating after the positive test result.
The organisation representing rank and file Defence Forces wants senior officers to investigate a COVID cluster at Custume Barracks in Athlone.
Twenty seven close contacts are now self-isolating after a soldier tested positive last week.
Newspaper reports suggest the person in question was present in the barracks and not restricting their movements when the result came through.
PDFORRA General Secretary Gerard Guinan says the full facts are not yet known: