Home Postcodes by state WA 6398 Postcode 6398 6398 is the postcode for 3 localities in WA: Broke, North Walpole and Walpole. Localities with postcode 6398BrokeWANorth WalpoleWAWalpoleWA Postcode 6398 State or territory Western Australia (WA) Localities 3 Council area Manjimup Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6397 · Postcode 6401