No, not during takeoff and landing. Even a tablet with an attached case with keyboard out will be queried - but it's OK if you can fold away your keyboard.
https://www.qantas.com/au/en/qantas-experience/onboard/communication.html - refer to the bullets under "Using your personal electronic device in flight mode":
- Secure hand-held devices by holding them or placing them in a seat pocket during taxi, take-off and landing. Items heavier than 1kg such as laptops will still need to be stowed.
You could put the laptop under the seat in front, I had mine in my tote bag under the seat in front on the weekend. Although I didn't use it all in-flight, it was there for ease of going through security.
