The Dividing Fences Act regulates building and repair of dividing fences in Queensland in certain cases.

In summary:

1. The agreement of your neighbour is NOT required if you propose to build a new fence inside your boundary, ie entirely on your own land and at your expense.

If you build a fence on your land (away from the boundary), the law of "adverse possession" may one day operate to divest ownership in the land between your fence and the true boundary to your neighbour if they subsequently occupy that strip of land for a length of time.