Two Sydney men have allegedly gone to drastic lengths to sneak illegal drugs into Stereosonic by trying to hide them around the venue days before the dance music festival.

Police have been called to Sydney Olympic Park twice in the past week to find individuals attempting to drill holes in buildings and stash dozens of ecstasy pills before the site goes into "lockdown" this week.

Zane Raffie, 21, at the Defqon festival. He has been charged with trying to conceal drugs at Sydney Olympic Park. Credit:Facebook

Saturday is expected to be one of the biggest days at Sydney Olympic Park since the 2000 Olympics, with 150,000 people attending four events - the Aus-X Open, the Short Course Swimming Championships, the Taylor Swift concert and Stereosonic, a one-day music festival featuring international DJs and electronic acts.