Roads Minister Michael Daley and Mulgoa MP Diane Beamer opened to traffic last Friday the first of three new north-bound lanes on the Mamre Road bridge.

The traffic switch will enable work to continue on the new and existing bridges, both of which are in the final stages of the $15million project.

The new bridge includes concrete barriers to improve safety for motorists.

``This project is about increasing capacity for traffic entering and exiting the M4 motorway so we can reduce congestion, particularly at peak traffic times,'' Mr Daley told the Star.

``The new bridge will expand local access, increase road safety and improve bus services.

``Pedestrians and cyclists will also benefit from the project with a shared pathway on the new bridge.''

At 11am on Friday, traffic heading north began using the new bridge, while the existing bridge had a single lane going south.

``Both the new and the existing bridges still require some work before all lanes can be permanently opened to traffic,'' Mr Daley said. ``When all three northbound lanes are open on the new bridge, motorists will have more capacity to enter and exit the M4 motorway.''

The two lanes on the existing bridge will be dedicated to south-bound traffic.

Ms Beamer said that the building of the new bridge was now largely finished.

``I'm pleased to be able to announce that the entire project is ahead of schedule,'' she said.

``This is a huge success for the St Marys residents and Sydney's west.''

The construction is expected to finish early next year.