Home Postcode finder WA Millbrook Millbrook postcode WA Millbrook is a locality in Western Australia covered by postcode 6330. Postcode 6330 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Millbrook business listing Be the first listing in Millbrook Common questionsWhat is the postcode for Millbrook?Millbrook, WA has the postcode 6330.What state is Millbrook in?Millbrook is in Western Australia (WA).Does postcode 6330 cover more than one suburb?Yes. Postcode 6330 covers 50 localities, so the postcode alone does not identify Millbrook. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.