Police strip-search powers could be in for a major shake-up with a court to rule on whether the examination of thousands of festival attendees was unlawful.

Officers did not have reasonable grounds to conduct the searches and failed to gain the consent of festivalgoers targeted, a class action filed with the NSW Supreme Court contends.

Initially contested by lawyers for the State of NSW, a major backflip was made in April when the government admitted it had unlawfully strip-searched the lead plaintiff running the lawsuit.

The woman – who AAP has chosen not to name for privacy reasons – attended the Splendour in the Grass festival in Byron Bay in 2018 were she was flagged by a police drug detection dog.

In a make-shift cubicle that did not offer privacy, the woman was made to remove all items of her clothing, including her underwear and tampon.

She was detained for about 30 minutes and let go after officers failed to detect drugs or any other prohibited items in her bag or on her person.

The state government’s admission in court did not extend to the more than 3000 people who have registered for the class action.

After a disputed hearing in May, Justice Dina Yehia will deliver her decision today.

This will determine whether the searches were conducted lawfully or constituted assault, battery or false imprisonment.

If the class action is successful, the state could be liable to pay out damages for fear, humiliation and loss of dignity caused by being searched.