A police officer who inflated the quantity of drugs found on a festival patron by nearly eight times was "muddled up" and made a mistake, an inquiry has heard.

Key points: The LECC has this week heard evidence of several police errors at the festival

The LECC has this week heard evidence of several police errors at the festival On Wednesday, it heard police errors could follow offenders for the rest of their life

On Wednesday, it heard police errors could follow offenders for the rest of their life The officer said it was easy to get "a little bit muddled up" when doing police paperwork

The officer, who cannot be named for legal reasons, also admitted she sometimes needed to "guesstimate" the quantity of drugs found on revellers when scales were not available.

She was on Wednesday accused of "sloppy work" at the Law Enforcement Conduct Commission (LECC), which is investigating whether police engaged in "serious misconduct" by strip searching a 16-year-old girl at last year's Splendour in the Grass festival.

The officer was involved in the festival's high-profile policing operation near Byron Bay in July 2018, including the strip-searching of patrons.

The commission heard the officer initially recorded the details of one music fan's arrest as being in relation to two tablets in a clear bag that weighed 0.4 grams.

But when she later prepared a statement of facts — which is used when an accused person faces court and is placed before a magistrate — the amount changed to 3.18 grams.

The latter amount was the exact same quantity from a separate case, but the witness denied she had accidentally cut and pasted from one case to another.

The officer said she would sometimes need to "guesstimate" the quantity of drugs on initial notices prepared in the field if scales weren't available.

"I think in the circumstances when you're doing all these charges it's quite easy to get a little bit muddled up," she told the commission.

"I've just made a mistake."

The spotlight has been on strip searches at the inquiry. ( Supplied )

Earlier this week, a 16-year-old girl gave a statement to the inquiry saying she had been left "humiliated" after a drug dog gave a positive reaction to her before she was asked to squat during the strip search.

No drugs were found on the girl, who said she now finds it difficult to trust police.

Officers later told the inquiry the search had been "unlawful".

On Tuesday, a senior constable admitted 19 strip searches he was involved in at the festival were unlawful because they failed to satisfy thresholds of "seriousness" and "urgency".

In more than 90 per cent of search cases at the festival, no drugs were found.

Chief Commissioner Michael Adams QC on Wednesday said there appeared to be "a pattern of, if not carelessness, inattention" by police.

"Human beings make mistakes all the time," he said.

"The point is you have certain duties to perform and it was important they were performed adequately and accurately."

The officer agreed there were significant consequences for accused people facing criminal charges in court.

"These are matters that involve the administration of justice," Mr Adams said.

"A conviction could follow someone around for the rest of their lives with terrible consequences.

"The law is designed to do that — to deter them."

The hearing continues.