Thirteen people were arrested for drug offences as part of a police operation at a music festival in Melbourne on Saturday.


Police rolled out the 'Passive Alert Detection' dog operation at the Listen Out music festival at the Royal Botanic Gardens, where a significant amount of the drug MDMA was seized with a street value of about $10,000.


Other drugs caught include ecstasy, amphetamines, cocaine and prescription drugs.


Police reported 12 of those arrested were referred to drug diversion programs and a 28-year-old man from Brighton was charged with drug trafficking and was bailed to appear in court at a later date.


Senior Sergeant Mark Pilkington said it was a worry that festival goers were prepared to use the "extremely dangerous" drugs.


"They are manufactured by criminals and users have no way of knowing what they're actually ingesting or the real risks involved," he said.