Counselling is not covered by Medicare. Sessions with a psychologist or an AASW-accredited mental health social worker are, with a GP Mental Health Treatment Plan — up to 10 individual sessions a calendar year.
Medicare does not cover counselling. Counsellor is not a registered profession in Australia, so there is no registration for the Better Access items to point at.
Sessions with a psychologist, or with a social worker holding the AASW's Accredited Mental Health Social Worker credential, attract a rebate when you have a GP Mental Health Treatment Plan or a referral from a psychiatrist or paediatrician.
A plan covers up to 10 individual sessions in a calendar year: six, then a GP review before the remaining four. Group sessions are counted separately.
The rebate is a fixed amount, not a percentage, so the gap is whatever the practitioner charges above it. Groundpath does not lodge claims — you claim with the receipt.