https://www.accc.gov.au/consumers/problem-with-a-product-or-service-you-bought/repair-replace-refund-cancel

These are direct quotes from the ACCC website (my bolding added for emphasis):

• When a product has a major problem, consumers can choose between a refund or replacement.

• When a business sells a product with a major problem, or a product that later develops a major problem, it must give the consumer the choice of a: refund, or replacement of the same type of product.