Sydney Motorway (SMC) is to call for expressions of interest on the WestConnex M4-M5 Link project in Sydney, Australia.

The M4-M5 Link twin tunnels are reportedly two of the longest tunnels in the country.

SMC chief executive officer Dennis Cliche said: “In calling for expressions of interest, we are asking the industry to put their most innovative ideas and designs forward to ensure we build the best possible infrastructure for Sydney.

“The M4-M5 Link is arguably the most important stage of WestConnex as it forms the vital connection between the upgraded M4 and New M5 to create a western bypass of Sydney’s CBD.”

"By separating the project into two packages of work, we can maximise efficiency and value for money throughout the procurement process for the design and construction contracts."

Construction on the first stage of WestConnex are underway, while a widened M4 tunnel is expected to be open to traffic by 2017.

Tunnelling works are being carried out on the M4 East between Homebush and Haberfield, and are scheduled to begin on the M5 in a few weeks.

The King Georges Road Interchange upgrade is expected to be completed by 2017.

The upgrade works will remove a major bottleneck on the M5 and ease traffic congestion.

It is reported that the M4-M5 Link will be completed in two phases, with the twin tunnels from Haberfield to St Peters to be built as a separate project from the Rozelle Interchange and Iron Cove Link.

M4-M5 Link project director Peter Jones said: “By separating the project into two packages of work, we can maximise efficiency and value for money throughout the procurement process for the design and construction contracts.

“The main tunnel works package is expected to include up to 9km of twin tunnels, associated ramps and supporting operational facilities with construction targeted to commence in 2018 and potentially opening to traffic in 2022.

“The interchange works package includes construction of the Rozelle Interchange and the Iron Cove Link, including the supporting green space of up to 10ha with construction targeted to commence in 2019 and opening in 2023.

“We are proud to be partnering with industry to deliver this vital link in Sydney’s road network and expect to achieve some exciting outcomes for motorists and the broader community.”

Upon completion, the M4-M5 Link will help motorists bypass nearly 52 sets of traffic lights, and reduce journey times between Parramatta and Sydney Airport by approximately 40 minutes.