Certain countries do require you to obtain a visa in advance if you wish to disembark the ship in port. You will need to check the visa requirements for the countries visited on your cruise itinerary. Countries such as China, Russia, India, Canada and the USA require all Australian passport holders to obtain a visa.
Visit the following link for advice on other travel requirements and restrictions at - https://apply.joinsherpa.com/travel-restrictions?affiliateId=fcau&originCountry=AUS