High visibility and plains clothes patrols are being conducted and will continue into the evening as punters leave the racecourse for licensed venues in the city and surrounds.

Police will also breath-test drivers leaving the racecourse.

Inspector Darren Hopkins, of Northern District Support Services, said the restrictions on general ticket-holders bringing alcohol into the racecourse had helped to reduce incidents.

People attending corporate marquees however, are permitted to bring in alcohol.

Inspector Hopkins said restrictions on operators in the venue had also significantly decreased the number of drunken incidents.

``We will have plain clothes officers patrolling the perimeter of the cup, as well as looking for anyone bringing alcohol into the venue,'' he said.

``You can't possess open containers of liquor in a public street.

``We also have the usual public order type patrols within the venue itself and there will be an increased police presence around the CBD and suburbs.''

Officers will also conduct liquor licensing checks to ensure that vendors adhere to the Responsible Service of Alcohol rules.