POLICE have issued a warning about a bad batch of LSD imprinted with an image of pop icon Psy doing a 'Gangnam Style' dance - after five teenagers were hospitalised at the weekend.

A 15 year-old-girl was rushed to hospital after taking the drug at a birthday party in Boambee East, near the NSW North Coast town of Coffs Harbour, on Saturday.

At 11pm the same night, police were called to another party in nearby Toormina because a 15-year-old boy who had taken a tab of acid had become violent.

Police have launched an investigation into the drug as it is believed a batch of the drug is circulating. An 18-year-old man was charged with the offence of supplying a prohibited drug after being interviewed by police today. He is expected to face Coffs Harbour Local Court on April 29.

Four Sydney teenagers were also rushed to hospital after overdosing on LSD at a beach party on Friday night.

Police and ambulance were called to Balmoral Beach, about 9pm, when four 17 year olds became violently ill from what is believed to have been a bad batch of the drug.

The teens were all taken by ambulance to Royal North Shore Hospital for treatment.

It is understood the teens had mixed LSD and marijuana, prior to becoming ill. Harbourside police said they were investigating where these drugs came from and what exactly they contained.

Detective Inspector Cameron Lindsay from Coffs/Clarence Local Area Command urged anyone thinking of taking illicit drugs to be careful.

"Taking any drug carries with it an unacceptable risk, but we would ask extra precaution to be taken in the area following these incidents."

"There is clearly more of this drug circulating in the community and anyone who consumes it carries with them the risk of permanent brain damage or death."