A multibillion-dollar underground motorway in Sydney’s south is at risk of further delays after the state government rejected an offer by contractors to complete the troubled project because it was deemed inadequate.
Despite throwing out the latest proposal, the government will give a consortium led by CPB Contractors, which had been building the M6 motorway between Arncliffe and Kogarah, time to return to the table with an improved offer.
The government has been at loggerheads with the consortium since tunnelling on the final section of the M6 was stopped indefinitely by a sinkhole that opened above one of the twin tunnels more than two years ago.
In the latest twist, the contractors handed their offer to transport officials on Wednesday, two days before a deadline to present a proposal to resume work on the M6.
Transport for NSW said the contractors had not yet met requirements to rectify the default identified in a notice issued more than seven weeks ago.
“Transport will consider all options available under the contract and at law to protect the public interest,” the agency said in a statement.
As of last month, the government had incurred more than $5 million in legal fees from the protracted negotiations with the contractors.
Transport for NSW’s most recent target date for the M6’s completion is the end of 2028, which is three years later than a previously planned opening in late 2025. The latter was later than the original completion date of 2024.
The M6 is now at serious risk of opening later than 2028 if the CPB-led consortium walks away from the project or the government tears up its contract and is forced to search for another builder. Even if a deal can be struck with the consortium, the project faces delays to the 2028 target date.
Roads Minister Jenny Aitchison said it was disappointing that the proposal from the contractors fell short in addressing concerns identified in the default notice issued in March.
“Our government is focused on delivery and seeing this project completed. Transport has advised me they will pursue all necessary steps to ensure outcomes that protect NSW taxpayers and the integrity of the project,” she said.
Coalition roads spokesman Mark Coure said the project had been stuck in limbo for more than two years, and people in southern Sydney were tired of excuses and more delay.
“Families, tradies and commuters have been waiting for far too long for this road. They deserve clear answers,” he said.
Work has been paused indefinitely on the final 244-metre section of the M6 since March 2024, when a 10-metre-wide sinkhole suddenly opened above one of the twin tunnels at Rockdale. Days later, another emerged about 150 metres away in a construction area on the eastern side of West Botany Street.
While transport officials maintain that there is an engineering solution to complete the tunnels, the two sides have been in a stalemate over liability for the cost of the halt to construction and the fix.
Budget papers from last June show the cost of the four-kilometre motorway is set to hit $3.193 billion, a $93 million increase on the most recent forecast.
The M6, which will funnel motorists onto the WestConnex motorway at Arncliffe, will be tolled when it eventually opens, but it will remain in government hands under the Minns government’s policy.
The CPB-led consortium declined to comment.
The long-running saga over the M6 project comes as the government seeks a fix for a stretch of the Great Western Highway in the Blue Mountains that has been closed indefinitely since March 12. After briefing contractors last week, Transport for NSW gave them just over a week to submit initial solutions so that shortlisting could start.
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Matt O’Sullivan is transport and infrastructure editor at The Sydney Morning Herald.Connect via X or email.