Commuters in Melbourne’s south-east are being warned of long delays over the next month as work ramps up on the Metro Tunnel.

Construction crews will be taking advantage of the quietest time on Melbourne’s roads and rails by excavating the final section of the Metro Tunnel entrance to make room for the new track that will connect the existing lines to the tunnel.

The summer construction blitz gets under way at the Metro Tunnel site in South Yarra. Credit:Jason South

During this blitz, buses will replace trains along the Cranbourne, Pakenham and Frankston lines between Flinders Street and Caulfield stations until January 30, affecting tennis fans heading to the Australian Open.

From January 4 to 12, buses will be extended to replace trains until Westall station on the Cranbourne and Pakenham lines, and until Moorabbin station on the Frankston line. Buses will also replace trains on the Sandringham line between Parliament and Elsternwick stations on various days throughout January.