About 8.18am, a 53-year-old Maida Vale man was cycling west along Hay Street, approaching the William Street intersection.
The pushbike collided with the 22-year-old woman, who was taken to Royal Perth Hospital with serious injuries but has since been released.
Police would like to speak to anyone who saw the cyclist or the pedestrian before the crash.
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READ NOWAnyone with any information about the incident should call Crime Stoppers on 1800 333 000.