For the purposes of taxation, same-sex relationships are not recognised. Therefore, any deductions and rebates apply as if you were single. This includes any medicare levy.

However, from 1 July 2009, same-sex couples will be recognised under taxation law and will be treated in the same way as opposite-sex couples and married couples. The Australian Taxation Office website contains information on the changes, whcih will affect tax returns from 2009-2010.