Police have arrested 71 people for drug possession at a Melbourne music festival.

Sniffer dogs were used to seize drugs including ecstasy, amphetamines and cannabis as the crowd entered the event at the Flemington Racecourse this afternoon.

Senior Sergeant Mark Pilkington says he is disappointed that revellers are continuing to bring drugs to festivals.

"We constantly warn people about bringing drugs to these events," he said.

"They're made by criminals [and] they don't know the effect it will have on them. We continue the warnings and these are the events we continue to see [drugs brought in]."