Technically speaking, no you cannot change them that easy. Our mattresses have very specific dimension for many reasons; therefore, they defer from the standard’s Australian sizes. For example, our queen size mattress has the following dimensions, 1500 x 1900 mm, the measurements for an Australian queen size mattress is 1530 x 2030 mm, which means that in terms of width they defer only by 3cm but in terms of height they defer by 13cm. As a result, your Australian size mattress would not fit in the wall bed frame due to its height.