Undertaking a search for a new design in determining the novelty characteristics on its essential features or, based on infringement issues, it may be very difficult if you do not master the differences among the Intellectual Property concepts.
In any case, your first step should not exclude a deeply study of the International Classification for Industrial Design:
Australian Designs Data Searching (ADDS)NEW!
(The data coverage is of all applications and registrations from 1986 and all registrations captured from 1973 to 1985 that were still active in 1985.)