A GP referral is not required to see a psychologist.

However, consultations without a GP referral, or with an ordinary GP referral will NOT receive a Medicare rebate. These consultations may be eligible for rebates from private health funds, depending on your level of private health cover.

Mental Health Care Plan:

A referral from your GP with a Mental Health Care Plan will allow you to access to a Medicare rebate.  As I am a clinical psychologist, your rebate will be $128.40 (July 2020).

A Mental Health Care Plan entitles you to have up to 10 Medicare rebates per calendar year.