By the letter of the law no, you must stay in the left lane unless overtaking a vehicle in front of you already in that lane.
The law states you must not enter a laneway if to do so would impede a vehicle already in that lane. Forcing them to slow is impeding so the expectation is you accelerate up to match or exceed their speed before they approach, or you wait until they pass before joining the lane.
Now, is it a sensible and accommodating thing to do, in many cases yes, but so often here you see people going from lane 1 to lane 2 at the hint of another can joining and forcing traffic in lane 2 to hit the brakes to avoid a collision.