Nearly 60 drivers out of 450 tested near the Lost Paradise Music festival have returned a positive result to an illicit substance.
Police tested the drivers on Peats Ridge Road yesterday.
Of the 450 tests, five returned a positive result to alcohol, while 59 were positive to drugs.
Police will wait for lab test results to determine whether the 59 drivers will face legal action.
22-year-old Joshua Tam died from a suspected drug overdose at the same festival on Saturday.