A police officer who conducted 19 strip-searches at last year's Splendour in the Grass has admitted none of them may have been legal, and only one revealed an item of interest: an antidepressant tablet.

The senior constable and one of his superiors at the music festival have both conceded to an inquiry into the alleged unlawful strip-searching of a 16-year-old girl that neither of them were aware of certain legal requirements for conducting the "invasive" procedure on minors.

A police sniffer dog inspecting revellers at the 2019 Splendour in the Grass music festival in Byron Bay. Credit:AAP

And a female officer who searched the minor without a support person said she "obviously didn't" turn her mind to the legislation and that inspecting the teenager's panty liner for drugs could've been "extremely humiliating".

The male officer - whose identity, along with the female officer's, is legally protected - also admitted to the Law Enforcement Conduct Commission (LECC) it was the "modus operandi" of police at the Byron Bay event to strip search everyone indicated by a sniffer dog, despite that not being enough to justify the procedure.