The two-day Yours and Owls music festival in Wollongong was the first of 12 festivals to have the NSW Health-run service as part of a controversial year-long pilot program.
The Minns government announced in December it would allow the trial of pill-testing at music festivals - a practice some other states have adopted - from early 2025.
Officers said they would keep a highly visible presence, including sniffer dogs, at the festival, except in or around the pill-testing site.
Police on Monday said they charged 23 people with possessing prohibited drugs across the festival's two days.
Some 51 drug detections, mainly for MDMA, were made and 24 future court attendance notices were issued.
Six patrons were ejected from the festival, police said.
Earlier, Health Minister Ryan Park said abound 100 festival-goers used the drug testing facility, which he said was a "really positive" result.
"This has been a policy that we've discussed with NSW Health and the team for a long time," Mr Park told ABC radio.
"It was about making sure that predominantly young people are as informed as possible when it comes to the use of these drugs."
He said 90 per cent of drugs tested contained the substance attendees had intended to purchase, with MDMA, ketamine and cocaine most common.
"People thought it was a really good addition to the music festival," Mr Park said of the trial.
Pill testing is legal in Queensland and the ACT, while Victoria launched a trial over summer.
Advocates say pill testing is a proven harm minimisation strategy used in many countries for decades, while opponents say it sends mixed messages about the risks of using and possessing illicit drugs.
15°C