Emergency services were called to the Swan River to rescue a woman on Thursday morning.

Police responded to an alert of a distressed person in the river near Riverside Drive in Perth about 5.40am.

The woman, in her 30s, was found clinging to a navigation buoy.

Two police officers swam to the woman until a boat arrived.

The woman was taken to Elizabeth Quay, where she was assessed by paramedics.

She was transported to Sir Charles Gairdner Hospital as a precaution.

Two police officers swam to the woman until a boat arrived.Two police officers swam to the woman until a boat arrived. Credit: Anthony Osmond/Anthony Osmond