Upvote:5
Assuming you have a valid visa to enter Australia, it works just as well if you enter Australia at Cairns as it does at Brisbane.
On a technical stop you may or may not leave the aircraft, and you may or may not be required to clear immigration. Whether you do or do not makes no difference to the visa you require. There are two possibilities:
In either case you clear immigration once. A single-entry visa will work just fine.
Make sure your visa will be valid at the date and time you touch down in Cairns.