When looking at maps, in Australia (at least in NSW state), some footpath are marked name as "trail" (e.g. https://goo.gl/maps/QWfxzDFjfrvBdtjcA) and some are named "track" (e.g. https://goo.gl/maps/YRfP1KoLZWFFqhYu5). If they refer to different kind of footpaths, have they officially been defined by authorities?
The endpoints of the trail and track you are linking to can be seen on Google Street View, so why not take a look for yourself? The trail is a dirt road closed off by a gate and the track is a narrow foot path.
But to quote Wikipedia:
In Australia, the term track can be used interchangeably with trail, and can refer to anything from a dirt road to an unpaved pedestrian path.
The standard on this would be the Australian/New Zealand Standard AS/NZS 4819:2011 Rural and Urban Addressing, which has been adopted by the Intergovernmental Committee on Surveying and Mapping.
The Standard is not freely available online, but parts of it have been republished by government authorities as part of their naming policy, e.g. the NSW Geographical Names Board's Address Policy. "Track" and "trail" are defined as follows:
Track - Roadway with a single carriageway. A roadway through a natural bushland region. The interpretation for both Track and Trail is limited to roadways, whereas in many areas (e.g. Tasmania) these are often associated with walking rather than vehicular movement.
Trail - See Track.