About 25,000 music fans flocked to Maitland Showground for the event, which featured the likes of teen sensation Billie Eilish, Hilltop Hoods, Hermitude, Duckwrth, Nick Murphy and '90s throwback Coolio.

NSW Police warned ahead of the event that 150 officers would be patrolling the showground, following the death of two young people at a music festival in Queensland last week.

Officers took a different tact to Groovin this year - people caught with drugs were excluded from the event, and many were issued on the spot fines of $400 rather than given court attendance notices.

Police arrested and charged a 17-year-old man who was allegedly found in possession of 54 caps of MDMA (ecstasy). He was granted conditional bail to appear at a Hunter Children's Court next month.

Port Stephens-Hunter Acting District Operations Inspector Kristin Marshall said a further nine people were handed fines, 15 were given court attendance notices and a number of youths were cautioned under the Youth Offenders Act.

With the help of five drug detection dogs, police recorded 34 positive drug searches - including illicit substances that had been dropped on the ground.

Acting Inspector Marshall said 15 people were taken to hospital including an 18-year-old man in a critical condition.

Police believe the teenager overdosed on MDMA. His condition had since "stabilised", and he is expected to make a full recovery.

Of the 15 hospitalisations, 14 were due to drug or alcohol intoxication while one was due to an assault.

Acting Inspector Marshall said the results were "not too bad" considering the size of the crowd, but that police were disappointed that despite the warnings, some still chose to partake in dangerous behaviour.

Want to relive the fun of Groovin the Moo 2019?

Listen to the Spotify playlist below to bring back your favourite moments.