Two assistant officers at the Brisbane Watchhouse have been suspended after allegedly using excessive force on a 16-year-old boy.

The two men allegedly involved, aged 52 and 41, were civilian assistant officers and not sworn police officers, the Queensland Police Service said in a statement.

The detainee was not physically harmed and did not need medical treatment after the May 10 incident, police said.

An investigation, which is still ongoing, was opened after the incident was reported to police "at a later date".