Police are being investigated over breaking the law when they asked a 16-year-old girl to strip naked and squat at last year's Splendour in the Grass, an independent inquiry has heard.

The teenager's strip search is being investigated by the Law Enforcement Conduct Commission (LECC) which independently investigates the police. It's assessing whether the police "engaged in serious misconduct" when strip searching the teenager.

Key points The strip search of a 16-year-old girl is being investigated by the LECC

The teenager was strip searched at Splendour in the Grass without a parent or guardian present

A parent or guardian must be present if a child between 10 and 18 is strip searched

The teenager says the search was "humiliating"

The teenager - who can't be named for legal reasons - told the commission in a statement that she had been lining up for entry into the 2018 festival when a drug dog sat down next to her. She said she was separated from her friends at the time, who were entering through another line.

The teenager said she was told by police to put her hands up and was led to another tent away from the entry gate.

"I felt completely humiliated, people were yelling out that police had someone... I was really scared as I didn't have drugs on me and I was alone," she said in her statement.

She says she told police that she was not in possession of any drugs before having her phone confiscated.

I became really frightened at this stage because I lost all contact with anyone I knew and I started to cry.

She said she was then asked to remove all her clothes, one by one, by a female police officer in the corner of the tent.

"I couldn't believe this was happening to me.... I couldn't stop crying. I was completely humiliated," her statement said.

"I was wearing a panty liner...she asked me to remove it to look at it.

"She asked me to squat on the ground...I squatted down in front of her and she squatted down and looked underneath me."

The inquiry heard the search did not uncover any drugs on the 16-year-old.

Has a strip search like this happened to you? Email Hack@abc.net.au. You can remain anonymous

Underage strip searches must happen in front of another person

The commission heard the strip search happened illegally because no one was contacted to be with the teenager while it happened.

"The strip search of a child between the ages of ten and eighteen must be conducted in the presence of a parent or guardian... or if that's not acceptable to the person being strip searched, another person whose presence is acceptable to that person," Counsel Assisting Peggy Dwyer said.

"The child cannot waive their right to a parent, guardian or independent person."

Immediately after the strip search, the teenager went to a free legal tent in the festival. A criminal lawyer in that tent said the 16-year-old was sobbing uncontrollably.

"I was extremely upset, I was sobbing... I did not stop crying for approximately twenty minutes," the teenager said in her statement.

I was shocked that the police would do this to me... Every time I saw a police officer at the festival I clenched up... I'd get clammy and hot.

"I feel I can no longer trust the police... I would have difficulty reporting something to police because I'd be worried I'd be falsely accused again."

Police say young people hide drugs in their "cavities"

The Chief Inspector of the Byron Bay area where Splendour is held - who can't be named for legal reasons - has told the inquiry many young women hide drugs in their internal "cavities".

"[A local service station] ran out of condoms...the general consensus is because people use them to secrete drugs...Young men get their girlfriends to do it," he said.

Police are only meant to carry out strip searches on people under 18 in urgent and serious situations. When asked if this search was justified by that law, the officer told the inquiry he "didn't know".

He said the main objective of drug operations was to find people supplying drugs at the festival.

Research has found police in NSW are using strip searches more than ever before, and many of them could be unlawful.

Draft recommendations from a coronial inquest into the deaths of six young people who took drugs at festivals have called for drug dogs to be scrapped from the events and pill testing to be implemented.

The inquiry is hearing from officers who coordinated the police operation and conducted the strip search at Splendour in the Grass.