A relationship register is an alternative to marriage that provides legal proof of a relationship. This may be useful in issues relating to tax, retirement accounts, government payments, immigration or medical emergencies. Most states and territories in Australia provide a relationship register,^[1] and similar registers exist in other jurisdictions, such as the Canadian province of Manitoba.^[2]

Relationships recorded in these registers are not included in Australian marriage statistics, which the Australian Bureau of Statistics identified as a possible data anomaly. While marriage rates have declined, the recently introduced relationship registers have grown in use.^[1] Although some couples have registered relationships because they are prohibited from marrying under the federal Marriage Act 1961 as amended by the Marriage Amendment Act 2004,^[3] other couples have registered as an alternative to marriage, thus reducing the marriage rate.^[1]