Even though doctors can set up private clinics they must either opt in or opt out of medicare. They also have the option of extra billing. If they opt out, the patient must pay up front and wait for medicare reimbursement. This may not be an option if adequate savings or credit is a problem. If the doctors have not opted out, they may charge additional fee not covered by medicare. For those with private healthcare insurance in addition to medicare, this is not an issue.
Take Ontario for example:
http://www.fasken.com/files/Publicat...ONSTRAINTS.PDF