Two of these cars were torched and dumped while one was involved in a police chase in Hamilton, while Police are still trying to locate the ford territory.
The Subura Impreza was stolen from Cape Bridgewater before being involved in the police chase and was later found burnt out in Merino.
The Toyota Camry was stolen from Otway Street in Portland and also later found burnt out near the intersection of Gorae Road and Surrey River Road at Gorae West.
Sergeant Martin Flannery says public assistance is vital for the investigation.
"We are looking for help from the public, any help at all," he said.
"We have had a number of calls come in with sightings, but we would appreciate as much assistance as possible with this.
"At this stage each of the scenes have been investigated by our crime investigation unit to gather evidence, in fact our CI team is still out making inquiries."
Police are follow up on several lines of inquiries, with it believed the same offenders involved in stealing the vehicles have also been linked to crimes in South Australia.
Anyone with information is urged to contact Crime Stoppers or the Portland Police station.