The John Holland and CPB joint venture (JHCBP), which has a A$722m (US$493.5m) contract, will now move on to the Western Harbour Tunnel (WHT) enabling works. It will build around 1.7km of tunnels as part of the project’s Southern Tunnelling Works from Rozelle to Birchgrove. This involves excavation and lining of the WHT driven tunnels, including ventilation tunnels, between the stubs provided by the Rozelle Interchange and Birchgrove Oval.

The WHT, a 6.5km twin tunnel, will be a second road tunnel under Sydney Harbour, connecting the Rozelle Interchange with the Warringah Freeway in the north of the city.

WestConnex is Australia’s largest infrastructure project, linking western and south-western Sydney with the city, airport and port in a 33km continuous motorway.

New South Wales premier Dominic Perrottet said Rozelle Interchange would be a critical link in Sydney’s road network.

“This milestone represents a major piece of the jigsaw coming together as we move another step closer to a better-connected Sydney, one with safer and less congested roads,” he said.

Minister for metropolitan roads Natalie Ward said the Rozelle Interchange would transform travel for motorists across Sydney.

“Rozelle Interchange is the final and signature component of the WestConnex project, which will ease congestion on the road network and provide Sydney motorists quicker and safer trips,” Mrs Ward said.