The NSW Police Force has admitted officers are breaching their powers to conduct strip-searches, and are not properly informing people they are performing a search.

An internal report from the force's Lessons Learned Unit (LLU) says there is no clear definition of a strip-search in state legislation, leaving it up to individual officers to interpret the law.

The November 2018 report details findings that police have been applying their powers inconsistently at different music festivals. It says a positive indication from a sniffer dog is not a green light to strip-search someone.

A police sniffer dog used to search for drugs at Field Day music festival in Sydney on New Year's Day this year. James Alcock

"Currently the legislation is open to interpretation and there is evidence of operational orders instructing officers that the removal of one piece of clothing constitutes a strip-search. Likewise, there is [sic] operation orders suggesting that an indication from a drug dog is enough justification to conduct a strip-search," the document, distributed for education and training purposes, says.

"The [NSW Police Force] needs to provide a consistent response to the legislation in order to provide a catalytic change."

There has been an almost 50 per cent increase in strip-searches over a four-year period between the financial years 2014-15 and 2017-18. The internal report says the rising number of strip-searches is boosting the risk of complaints, and lawsuits over unlawful searches are increasing.

One man successfully sued the state for more than $112,000 last year after being wrongfully strip-searched by police patrolling in Darlinghurst.

Under NSW law a police officer can carry out a strip-search in the field if he or she suspects on reasonable grounds that it is necessary for the purposes of the search and that the seriousness and urgency of the circumstances make the strip-search necessary.

A NSW Police spokesperson said in a statement that all recruits were taught in-depth about police powers regarding searches and strip-searches, with officers' requirements recently circulated throughout the force in a one-page guide.

"Education and Training Command has developed ongoing learning packages including video packages outlining scenarios where searching and strip-searching is and is not appropriate and intensive training material for delivery to all operational police officers," the spokesperson said.

NSW Police Commissioner Mick Fuller recently sparked confusion when he classified officers asking people to take off their shoes and socks as within the ambit of a strip-search during an interview aired on 2GB radio.

According to legislation, requiring someone to remove the outer layers of his or her clothing, including shoes and socks, falls within the scope of a general search. Greater hurdles are applied to strip-search powers.

Mr Fuller's interview was in response to a Herald article revealing almost 300 minors, including a 10-year-old, were strip-searched by police over a two-year period between the financial years 2016-17 and 2017-18.

"It’s not the case that all of these 300 kids were stripped down but nevertheless it’s something we do take seriously," Mr Fuller told host Ben Fordham.

A police officer uses a sniffer dog at Field Day 2019. James Alcock

The LLU report says step-by-step instructional stickers have been issued to remind officers of their legal requirements, and educational screen savers have been displayed on police computers during the summer festival season following a "breakdown in the knowledge transfer process".

"The LLU identified that clarification was needed surrounding the strip-search definition with accompanying guidelines or instruction," the report says.

The NSW Police Academy has started a review into all training material taught to recruits and the commander of the central metropolitan region is educating police on strip-search powers, the document says.

According to the police report, "lack of compliance" stems from confusion about the definition of a strip-search and police not properly informing a person they are conducting one.

"The legislation provides no clear definition on the minimal level of clothing required to be removed to define a strip-search," the document says.

The NSW Bar Association has joined other high profile legal figures, including former director of public prosecutions Nicholas Cowdery, QC, in calling for legislative change. Bar president Tim Game, SC, said "objective criteria" needed to be introduced into the legislation to limit the discretion available to the individual officer.

"If you tighten up the regulatory context then all the way through it will be enforced in a more rigorous way," he said.

The document states the use of drug detection dogs at major public events such as the Mardi Gras and music festivals has come under public scrutiny, with police drug detection methods described by a sitting NSW coroner as "low hanging fruit".

"A positive indicator from a drug detection dog must also be accompanied with other evidence obtained through observation, asking questions and using intelligence to meet the burden of proof required for 'reasonable grounds'," the report says.

An LLU analysis found some orders for police operations at events included their own definition of what a strip-search was.

The operation plan at last year's Defqon.1 festival in Penrith stated "once the drug detection dog makes an indication, the person of interest will be approached by police and removed to the provided secure area where that person can be searched."

The report recommends an operational template be rolled out for events where sniffer dogs are used to ensure consistency, and that "best practice" guidelines and educational products, including videos, be developed.

According to the document, one example of 'best practice' is the use of a "triage officer" to either permit or refuse a strip-search going ahead at events.