Four Suspected Drug Overdoses At Victoria's Rainbow Serpent Festival

Four revellers are recovering in hospital after being suspected of overdosing on drugs while at Victoria's notorious regional Rainbow Serpent Festival over the long weekend.

A man, aged in his 40s, on Sunday afternoon became the fourth person to be taken to Ballarat hospital linked to drug-taking since the music event kicked off on Friday, Ambulance Victoria said.

A fifth person has been hospitalised over the weekend due to a medical condition.

Victoria Police caught 22 people with drugs in the 24 hours to 7.30am on Sunday, issuing 17 drug diversions or cannabis cautions.

Officers arrested four males and a female for various offences including trafficking and possessing a drug of dependence, counterfeit cash, proceeds of crime and assault.

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Image: Rainbow Serpent Festival Facebook

A 17-year-old boy arrested for drug trafficking will appear at a children's court at a later date while a 25-year-old French woman on the same charge is due in court on Tuesday.

Sniffer drugs had been brought into the festival in Lexton, near Ballarat, to assist.

Three festival goers were injured, one seriously, after a truck rolled into a campsite on Thursday afternoon.

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The four-day event has been held amid political debate about pill testing after five people died from suspected drug overdoses at NSW festivals since September.

The festival has also been marred by controversy after last year's two reported sexual assaults, five arrests for drug possession and 44 people testing positive to drug-driving.

The event wraps up on Monday.