A shared path is a paved area particularly designed (with appropriate dimensions, alignment and signing) for the movement of cyclists and pedestrians - Austroads Glossary of Terms.
A Shared Use Path is a path open to the public that is designated for, or has as one of its main uses, use by both cyclists and pedestrians, but does not include a separated footpath or a footpath adjacent to a road - Austroads Guide to Traffic Engineering Practice.
Shared Use Path Widths
Austroads recommends the following path widths.
It is important that a shared path be signed as such, as in a number of states bicyclists are not allowed on footpaths unless they are under 12 years of age or are accompanying a rider under 12 years of age.