MAIN Roads WA will be upgrading the intersections of Orrong Road and Archer Street, and Orrong Road and Alexander Road.
Construction is expected to start next month and take about six weeks to complete.
The relocation of services is already under way.
The majority of the work will be undertaken at night due to the high traffic numbers in this location.
This project is funded by the Australian Government's Black Spot program.
The upgrade includes:
Widening Orrong Road southbound from three to four lanes to provide a double right turn into Archer Street westbound.
Removing the right turn signal filter at the Archer Street intersection.
Relocating the pedestrian crossing at Archer Street to allow for a staggered, safer crossing of Orrong Road.
Upgrading street lighting.