Motorists will endure 11 days of traffic snarls on St Kilda Road in a harbinger of the years of Metro rail tunnel works hell to come.

St Kilda Road will endure three years of heavy traffic when it is reduced from four lanes in each direction to just one each way from next year. The section affected is between Bowen Crescent and Kings Way/Toorak Road West.

But a precursor of the pain will come in the school holidays when St Kilda Road will be down to one lane each way for 11 days from July 1. During this time tram commuters will need to take replacement buses.

Once that work is complete, from July 12, St Kilda Road will have a lane each way restored between Bowen Crescent and Kings Way/Toorak Road West.