The defence of claim of right could be raised where a person holds an honest belief of legal entitlement. The belief does not need to be reasonable, however, the reasonableness of a belief may become a relevant factor when determining if it was in fact held. The claim of right negates dishonesty. The legislation which deals with this is section 9.5 of the schedule of the Criminal Code Act 1995.
Does the belief need to be reasonable?
In order to be successful in this defence, you would need to show that there was an honest belief held. It does not necessarily have to be a reasonable one. Reasonableness, or rather unreasonableness becomes a relevant consideration when determining if an honest belief was really held, and how plausible that assertion is.
What must be proven?
The accused who raises the defence of claim of right, carries the evidentiary burden. The accused has to show that there was an honest belief. The prosecution has the persuasive burden in order to rebut the claim. This means that the prosecution has to negate the defence raised. The prosecution must attempt to prove that the accused did not have an honest belief. There are of course limitations on the claim of right such as that the claim must be for a legal right as a moral right is insufficient.