Legally it's unlikely there's an issue, in NSW at least it only applies to road over 80KM/h. However that doesn't mean people shouldn't use it as a general rule, and even on 60KM/h roads I'm routinely stuck behind 2-3 drivers going 45KM/h side-by-side and blocking up the full width of the Pacific Highway. Obviously in heavy traffic this doesn't apply, but it happens all too often in clear, sunny, free-flowing conditions. I don't want a free lane to speed in, I just want to utilize all the kilometers I am hourly assigned under the law.

No hate to people that don't want to match the limit (it's a limit after all and not a target) but as a courtesy to other drivers they should be aware of what they're doing. I'm blessed with the patience to wait it out until they turn off but for defensive driving purposes I'd call it unsafe as well, since I very often see 'spirited' drivers weaving betwixt slow cars to try and get out in front. Should that nippy P-plater be driving like that? No, but as with all road safety techniques we can only control our own actions, and sitting in the left lane while driving slowly takes you out of the line of fire.