From Bushwalk Australia
Scrub Bashing is similar to Bush Bashing with the addition that the walking explicitly requires pushing (or 'bashing') through very dense and scrubby vegetation.
Navigation while scrub bashing is very difficult, because not only is there no track, but because it is quite often difficult to see for any significant distance in any direction and to maintain progress in a consistent direction.
Apart from the difficulties of navigation, progress while scrub bashing is very difficult due to the physical exertion required to 'bash' through (ie, to push through, between, over and/or under trees, shrubs, tussocks, logs, rocks, etc), and the physical abrasion experienced from rough and sharp vegetation (including sticks, spiked leaves and cutting grass blades).
Scrub bashing results in very slow progress, such that an entire day may be required to cover the same distance that would otherwise be covered in an hour of walking on an easy track.
It also results in significant pain to exposed areas of skin due to numerous repeated scratches, scrapes and cuts. If significant stretches scrub bashing is anticipated, it is recommended to wear long trousers (as well as gaiters) and long sleeves.
After a period of time scrub bashing, the lack of progress and the physical exertion and pain frequently results in substantial metal anguish.
Vegetation that often grows thick enough to require difficult scrub bashing includes: Tea Trees, cutting grass, horizontal.