A friend just put me on to this so thought I would share.
Member offer
During Vivid Sydney, Members have two ticket options:
Unlimited Rides Pass valid for Sunday - Thursday from 6pm: $13.00 (saving $12)
Unlimited Rides Pass valid for Friday-Saturday from 6pm: $18.20 (saving $16.80)
Vivid Sydney 2019 Trading Hours (24 May to 15 June)
Sunday to Thursday 6pm-10pm
Friday to Saturday 6pm-11pm
Please note: This ticket can be redeemed after 6pm during Vivid, 24 May to 15 June 2019. If you wish to purchase a general admission ticket to visit Luna Park Sydney outside of this period. Need to purchase the ticket via nrma website link.
Good deal. Keep in mind that unlimited rides are actually limited by the long queue time.