Could the M6 be Sydney’s unbuildable motorway due to sinkholes and a reverse fault?

The M6 motorway project is 90% completed but its fate remains up in the air as the CGU has said it will down tools due to the impact of a ‘complex faulting zone’. Photograph: Transport for NSW

A 245-metre section of a new Sydney motorway tunnel plagued by sinkholes and a “challenging” geological feature will bring a $3.1bn transport project to a grinding halt unless an 11th-hour deal is reached.

The M6’s new twin 4km tunnels, connecting Sydney’s south to the wider motorway network, were approved in 2019 and scheduled to open in 2025.