Here is a link to the Stamp duty form: https://treasury.nt.gov.au/__data/assets/pdf_file/0017/481040/F-SD-001.pdf
Only SMSFs registered in Northern Territory require stamp duty.
Northern Territory
The deed is liable for $20 duty. To pay the duty, the executed deed must be lodged with the Territory Revenue Office. You will need the stamped deed to take to the bank to open the SMSF bank account.
Step 1: Fill in the form
Step 2: Print off the trust deed and have all the members and witness sign the last page again. Date the signing the same as the original. Then mail the docs to…
Territory Revenue Office.
GPO Box 154, Darwin NT 0801.
If you need to follow up of have any queries about their process you can call the Territory Revenue Office on 1300 305 353.
Step 3: You will get the original docs mailed back to you with the required stamps. With the docs you will have an invoice for $20 payable to the revenue office that can be paid via EFT online.
Step 4: Take the stamped docs to the bank (or email if requested to do so)