Lexis Nexis AU has a new legal dictionary app for iOS devices.
The Butterworths Concise Australian Legal Dictionary has ‘only’ 7600 words — so doesn't seem to be the full thing. But more portable than the hard-copy. (The full edition is still only available in the 1997 edition; the concise paperback was last published in 2004 with 8000-odd entries.)
If you already have a LexisNexisAU subscription, I reckon accessing the dictionary through the web-portal would provide greater coverage. But otherwise, at $20, this is a great buy for advocates and students.