Australians are seriously dependent on other countries for the food they eat every day. Most of that food arrives by sea. Any interruption to supplies would materially affect the diet of the nation to the point of hunger.
It is an absolute fallacy and a hugely deceptive piece of propaganda propagated by farmer organisations and politicians to claim that Australia is self sufficient in food. Nothing could be further from the truth. In 2020 food to the value of $22 billion was imported into Australia, an increase of nearly 10% on the previous year. The retail value of that food is about $44 billion.
The food processing industry in Australia is a mere shell of what it used to be. Over the last twenty years food processors in their droves have closed their doors or left the country because they could not compete on price with food imported into this country, but grown and processed in America, New Zealand and the EU including the UK, countries who all have a standard of living equal to or better than Australia.
These three advanced economies sell to Australia, at a profit, food worth over $10 billion a year (over 50% of all food imports) and increasing annually. This food is now part of the staple diet of Australians. It is worth repeating, if for any reason the supply of this food is interrupted, the diet of all Australians would be severely stressed.