Our Work

M6 Motorway


M6 Motorway


The M6 Motorway is set to be Sydney’s newest motorway, encompassing the projects previously referred to as SouthLink, M1 Gateway to the South and the WestConnex Southern Extension. With Stage 1 receiving planning approval from the Department of Planning, Industry and Environment in December 2019 and tenders called for construction in April 2020, the M6 is a key element in connecting Sydney’s south to the wider motorway network.

Ranbury’s scope of work includes the following:

  • Capital cost estimates for both reference design at 20%, 80% and pre-tender cost estimate for the M6 tunnels, cut and cover for associated surface works
  • Pre-tender cost estimate
  • Capital cost estimates for both reference design at 20%, 80% and pre-tender cost estimate Council early works and recreational facilities
  • Risk assessment and quantification for inclusion in risk modelling
  • Development of risk-adjusted P90 cost estimates
  • Constructability and staging reviews and reports
  • OPEX cost estimates
  • Ongoing estimate support during the construction phase of the contract for valuation and assessment claims.

The M6 Stage 1 will enable motorists to bypass up to 23 sets of traffic lights on the Princes Highway between St Peters and Kogarah. It will also remove around 2000 trucks per day from surface roads.

The entirety of the M6 Stage includes:

  • Two four-kilometre tunnels linking the new M5 Motorway at Arncliffe to President Avenue at Kogarah
  • Ramps between the main motorway tunnel and the surface intersection at President Avenue
  • Tunnel stubs for a future connection south to extend the M6
  • A new intersection at President Avenue, including the widening and raising of President Avenue at this location
  • Provision of new shared cycle and pedestrian pathways connecting Bestic Street, Brighton-Le-Sands
  • Motorway support infrastructure including tunnel ventilation systems and a motorway control centre
  • New services utilities including a permanent power supply line
  • Minor adjustments to local roads in the project area

The project is expected to open to traffic late 2025.