Will I have to pay duty under the land rent scheme?
People participating in the land rent scheme will be required to pay duty once, at the point of entering the scheme. If, at a later time, you decide to purchase the land, you will not be required to pay additional duty. The payment of duty is due within 90 days of exchange of contracts and is dependent on the unimproved value of the land. For further information regarding any applicable duty required, please contact ACT Revenue Office or visit www.revenue.act.gov.au.
https://www.beyondbank.com.au/need-help/will-i-have-to-pay-duty-under-the-land-rent-scheme