Melbourne Police confirmed that they seized ecstasy, amphetamines, cannabis and cocaine at the Melbourne music festival held at Flemington Racecourse and subsequently arrested 20 members of the public.
According to The ABC, one person was issued with a penalty notice, nine were cautioned and 10 were referred on to a drug diversion programme.
Big Day Out promoters said that 42,000 people attended the event and around 130 people were treated by paramedics for heat-related issues. At last year's Melbourne event, 1,400 people were treated for dehydration in the hot weather.
Kanye West pulled the largest crowd of the day as he performed hits such as 'Love Lockdown', 'Gold Digger' and 'Stronger' from a cherry-picker hovering above the audience.
Other acts at the event included Soundgarden, Boy & Bear, The Living End and Kimbra.
A 34-year-old man also died at the Rainbow Serpent festival in Western Victoria over the weekend, but police have not confirmed if the incident was drug-related.
> Kanye West takes to stage 45 minutes late at Big Day Out Gold Coast show
> New Zealand's Big Day Out music festival axed
Watch Kanye West's 'Love Lockdown' video below: