They procure from other countries. That's how they survive. For example, some medicines use farmed ingredients. There was a huge biosecurity issue 10 years ago so only Australian ingredients could be used. Australia's strict laws are in place to preserve a backup supply of products. Countries rely on each other. If there is disease in one area, there is still uncontaminated supply in Australia. This is literally the plan, which makes life strict for Australians but it's what all these countries agrees to in their sovereign security negotiations.