Police will use extra powers to search revellers at St Kilda beach and other Australia Day hotspots for drugs and weapons as they crack down on alcohol-fuelled violence.

Assistant Commissioner Libby Murphy said police had been given "specific powers" to search people, with the St Kilda foreshore alcohol ban extended to take in the entire Port Phillip council area for the long weekend.

There will be a large police presence at St Kilda and other beach hotspots on Australia Day. Credit:Darrian Traynor

"What that does is it sends a really strong message: we're not putting up with any poor behaviour ... so be aware, if you're in that area, we'll be searching you," she said.

St Kilda's foreshore has been marred by alcohol-fuelled violence over the summer months in recent years. A series of alarming attacks in 2018 prompted the City of Port Phillip to ban alcohol on the beach.