No, it is not possible to upgrade a Qantas flight with Malaysia points.
Unlike Star Alliance, for example, oneworld does not have a generalized scheme for point-based upgrades on partner flights. That is, you can use points in one oneworld program to redeem a premium ticket on another oneworld carrier, but you cannot use them to upgrade a paid ticket on a partner to a more premium cabin. Individual member airlines do have arrangements with other members— for example, you can use American AAdvantage miles to upgrade on British Airways and Iberia— but you must check with the carrier.
Qantas makes upgrades very difficult in general, and does not allow upgrades using points from any partner airlines. There is no mention of partners on their Using Points guide. "Classic Upgrade" rewards are only listed as available using Qantas/Jetstar upgrade instruments.
Even for a Bid Now Upgrade, you can only use Qantas points or cash:
You will need to bid using a combination of Qantas Points and money if you are a Qantas Frequent Flyer*, or money only if you are not a Qantas Frequent Flyer. A minimum Points and money amount apply.