The Department of Justice (DoJ) is investigating an incident inside Maghaberry jail which led to a woman prison officer needing treatment.
Edwin Poots, DUP MLA for Lagan Valley, had written about the incident on his Twitter account.
He said on Sunday: “A prison officer scalded with hot water and five colleagues injured.”
However, the DoJ said that the number of officers hurt stood at four.
This happened during what it described simply as “an incident involving a prisoner at Maghaberry on Sunday afternoon”.
It added: “One officer – a female – received treatment for her injuries.
“In line with Prison Service policy, a full investigation will now be carried out into the incident.”