The Prison Officers' Association is questioning the hosting of the event.
The Prison Officers' Association is writing to the director general to question if any action is being taken against those who attended a retirement party in the Midlands prison.
They say up to fifty people, including senior managers from the Irish Prison Service travelled to the event for retiring governor Ethel Gavin on March 27th.
The Director General says clear instruction was given that any large gathering, or large assembly of staff was not permissible.
General Secretary of the Prison Officers' Association Gabriel Keaveny says a number of questions need answering: