Drivers and pedestrians now have access through the new Bankstown Underpass with the opening of two lanes, one in each direction and a pedestrian footpath.
Mayor of Bankstown Clr Tania Mihailuk said: "The people of Bankstown have been waiting more than 30 years for the Underpass to be widened.
"Bankstown City Council has invested more than $6.5 million into these works.
"With this project finally being realised, the expansion of this vital transport link for our city will greatly assist drivers and pedestrians travelling through Bankstown."
Director City Assets and Infrastructure, Matt Stewart said: "As a result of ongoing bad weather project completion has been delayed. However, efficient project management has allowed Council to complete stage one of the project and partially open the Underpass to traffic and pedestrians."
Once complete Bankstown's new Underpass will include four traffic lanes, signalised intersections, pedestrian pathways and improved bicycle access.
As work on the final stage of the Underpass improvements project continues, pedestrians and drivers are encouraged to obey all traffic and safety signs to ensure safe commuting between North and South Terraces.