You must declare or dispose of any prohibited or restricted goods before you reach customs. Even if you do not declare any goods, your baggage is subject to inspection by a biosecurity officer. X-ray machines and detector dogs may be used. If you fail to declare or make a misleading or false declaration, your items may be seized and you may be subject to penalties such as fines or even imprisonment for criminal offences. You will not be penalised if you declare all your goods, even if they are not permitted in Australia.