NITV News understands the incident allegedly occurred in mid-January, and that the officer responsible was suspended at the 'earliest opportunity' - the following morning.
On Tuesday morning the that the officer was 'marched off the site' after management was made aware, and that the prisoner was 'vulnerable' and being kept in an observation cell at the time.
It remains unclear how long the prisoner went without food, or if any medical treatment was received.
The Victorian Aboriginal Legal Service (VALS) said while they couldn't provide extensive comment until they have more information, they were unimpressed with the allegations.
"VALS is deeply saddened by the alleged inhumane treatment of an individual held in custody at Ravenhall," a statement read.
"This incident highlights the importance of greater vigilance in the oversight of corrections staff. Aboriginal lives matter, and everyone deserves to be treated with dignity and respect."
GEO Group Australia manages the facility and is responsible for hiring and paying employees has refused to comment on whether or not the officer was suspended with or without pay, or for how long.
Corrections Victoria told NITV News that they could not comment on the matter, while GEO Group Australia said an investigation was ongoing.
"A staff member at Ravenhall Correctional Centre has been suspended from duty pending an outcome of an investigation into a possible breach of GEO’s Code of Conduct," a statement from GEO Australia read.
"GEO has a strong code of conduct in relation to basic human rights and prisoner welfare and has a zero tolerance policy in relation to proven breaches of its code.
GEO recognises the needs of all prisoner groups and treats all prisoners with dignity and respect. As the investigation is ongoing, it would be inappropriate to comment further."
