Work on Sydney’s $3.1 billion M6 Stage 1 motorway will halt indefinitely after the lead contractor, CPB, formally terminated its deal with Transport for NSW, citing unexpected tunnelling conditions.
The decision, revealed in an email to workers on Monday, follows months of delays and controversy after two major sinkholes emerged along the southern section of the project, which was already plagued by disputes over construction methods and liability for cost blowouts.
The joint venture of CPB, Ghella, and UGL (CGU) told staff that “tunnel excavation … has been on hold for almost a year now due to the impact of unique adverse ground conditions caused by a complex faulting zone, including a high angle reverse fault (never seen before in the Sydney Basin).”
The correspondence continued: “The presence of such ground conditions could not have been anticipated by anyone.
“They were only discovered once tunnel excavation in the Caverns area was carried out … It is now apparent that a compliant design solution cannot be achieved to overcome these challenging ground conditions.”
All work is set to halt by June 30, leaving the project’s completion date and final cost uncertain.
The escalating dispute between the contractor and the NSW government means taxpayers could face tens of millions in legal fees, with the government and CGU blaming each other for the delays and design failures.
The M6 motorway, designed to link the M8 at Arncliffe to Presidents Avenue in Kogarah, has been beset by engineering warnings, riskier construction choices, and community frustration since a 10-metre-wide sinkhole appeared at Rockdale in March last year.
Transport for NSW maintains that responsibility for tunnel design rests with the contractor, while Opposition roads spokeswoman Natalie Ward called for urgent answers, stating: “If these allegations are true, serious questions must be answered not just by the contractor, but by Transport for NSW and its procurement oversight.”
NSW Roads Minister Jenny Aitchison expressed disappointment, adding: “All aspects of construction delivery are the responsibility of the contractor.
“It is a reality of large infrastructure projects that issues will arise and need to be dealt with by the contractor according to the contract.”
With construction on the damaged section stalled for over a year, and the government already spending more than $5.54 million in legal fees, the future of the M6 remains in limbo, with local communities and motorists left waiting for a resolution.
