Two cars have collided near the intersection of Goddard Street and Dixon Road in Rockingham.
Initial reports suggested people could be trapped in both vehicles, and one car could be on fire.
All occupants are now out of the vehicles, and three people have non-life threatening injuries.
A male in his 80's is being taken to Royal Perth Hospital.
Two females - one in her 70's and one in her 50's - are being taken to Fiona Stanley Hospital.
St John Ambulance and DFES were on site.