Police and the Waitaki Guardians will be attending the event at Whitestone Contracting Stadium and people caught drinking or possessing alcohol within the grounds have been warned they might be removed.
Police have been working closely with the Waitaki District Council, schools and the North Otago Rugby Football Union to make it a successful day, Constable Ross Lory said.
"We all aim to create a safe environment where all people can enjoy the day. It is one of Oamaru's busiest days.
"There have been no issues in the past and the police will be in attendance at the game and during the evening."
Waitaki community safety officer Alison Banks said the day was steeped in tradition and friendly rivalry and the decision to make it alcohol-free would not change that.
"It is simply a measure to ensure that the day is for everyone to enjoy, free of trouble."
Neither of the two major school rugby games in Dunedin today, Otago Boys'-King's at Carisbrook and John McGlashan-Kavanagh at Kettle Park, will be designated alcohol-free.
Otago Boys' rector Clive Rennie said there had been no alcohol-related issues with the interschool that he could remember.
Kavanagh principal Paul Ferris said there was no reason to look at an alcohol-free policy because there had been no problems in the past. His school, like others, expected supporters and ex-pupils to be more interested in watching the game than causing trouble.
The issue of alcohol at school rugby games entered the spotlight last week when police breath-tested supporters at the interschool between Christchurch Boys' High School and Christ's College.
