Is it possible to use Qantas Points to upgrade my Qatar flight?

We have an economy class flight Melb - Adelaide - Doha - Zagreb booked for later in the year. Do you know if we can use qantas points to request an upgrade?

No, unfortunately you cannot use Qantas points to upgrade on other partner airlines. You can only upgrade on Qantas planes booked with a Qantas flight number (i.e. not a code share).