Looking at random dates, Park Hyatt Melbourne becomes as low as ~$215 a night. Weekend availability for the coupon. appears limited though.
To qualify for the Hyatt Friends & Family rate for healthcare workers, you must be a healthcare worker and request special offer code THANKYOU at the time of reservation. Stays must be booked in advance for travel completed by December 31, 2022. You will be required to provide certain information about your position in healthcare to complete your reservation, and verification of employment will be requested at check-in. Hyatt reserves the right to convert your stay to the then current Hyatt Standard Rate if you are unable to provide verification at check-in. This offer may only be used for a maximum of 7 nights per stay and up to 2 rooms per stay.