Two days ago I was hitchhiking back to Sydney from Queensland.
I'm sure it's legal to walk along the M1, Pacific Highway on the NSW side since there were signs about bicycle crossings, no signs saying "no pedestrians" at the on-ramps, and a couple of police vehicles drove past me without stopping, some of which definitely made eye contact with me.
On the Queensland side there were definitely "no pedestrians" signs at the on-ramps.
As it's quite tricky to get onto the Pacific Highway to hitchhike in Queensland it's good to know exactly where I need to get to before I can hitch directly on the highway.
I don't think it's right at the border but I may be wrong. It may have to do with whether a stretch is classed as "motorway" or "highway" etc or it may be a combination of that and which state the section is in.
It seemed that it was definitely OK to be walk along this road from Chinderah heading south, but maybe I would've been fine getting on some distance further north.