Oliver and jump jockey Paul Hamblin - who was banned for 30 days - failed trackside breath tests at the Warrnambool racing carnival.
Both riders were stood down from races later in the day.
Oliver, 43, pleaded guilty and says he drank with dinner the previous night, adding to stewards: "I am very embarrassed and sorry about it."
In 2012, he was banned for 10 months after placing a £6,500 bet (AU $10,000) on a rival horse.
Melbourne Cup-winning jockey Damien Oliver has been banned for 29 days for failing an alcohol test before a race.