John Holland will deliver the $324m early works package for Victoria’s biggest public transport project, Melbourne Metro.

The contract includes excavating massive shafts in the centre of Melbourne as part of preparations for the tunnel and five new underground stations.

It will involve excavation of huge open shafts adjacent to Swanston Street to enable the underground construction of the two new city stations built as part of the $10.9b project.

Premier Daniel Andrews said the shafts will be up to 35m deep – more than 11 storeys below the ground – and involve the excavation of 34 Olympic-sized swimming pools worth of soil and rock from beneath the city.

Excavation of the CBD North Station will involve two shafts – at Franklin and A’Beckett Street – which will be covered by massive acoustic sheds to reduce noise for neighbouring residents and offices. Construction of CBD South will involve the partial demolition of the carpark underneath City Square.

Other works in the package include the relocation and protection of up to 100 utilities, including gas, power and telecommunications services, and the 120 year old brick main sewer line under the Domain interchange.

These works will start within weeks, with work on the stations shafts to begin next year, following the conclusion of Environment Effects Statement (EES) process currently underway and formal planning approval for the project.