can we do intensive units as international students?

in Sydney student it says that based on our visa requirements we need to take a full-time study load of 24 credits per semester.

in sem2 currently & was thinking of switching majors, but I will be 1 unit behind which I should’ve taken in sem1 this year, which I will need to do sometime before my 3rd year, and I don’t want to push it to 4th year as I might consider doing an appended honours degree instead of advanced studies coursework.

However I was wondering whether doing it as an intensive would mean I need to like pay extra? Or would I be able to adjust the cost of those 6 credits later in my 4th year?