According to the Passenger Movement Charge Collection Act of 1978, there are 12 categories of exemptions. One of which is being a transit passenger. In 1978, a transit passenger is one who stays in Australia less than 48 hours. In Australia's tourism website, they listed 24 hours.
If your WEL-SYD-HNL was on one ticket, the charge should not have been collected by the airline to begin with. Same for HNL-SYD-WEL.