Lawyers and doctors have weighed in on the marriage equality debate, with the two professions coming together to support same-sex marriage.
The federal government is asking the public to decide the marriage equality issue via a postal vote, which will determine if the law should be changed to allow same-sex couples to marry.
The survey will be sent out to everyone on the electoral roll and it will be run via the Australian Bureau of Statistics (ABS) in September subject to a high court challenge.
NSW Law Society President Pauline Wright said denying couples of the same sex the choice to enter a civil marriage contravened the principle of equality before the law.
"The Law Society of NSW is committed to ensuring that all Australians are equal before the law in rights and dignity, regardless of sexual orientation or gender identity," Wright said.
"Failing to recognise same-sex marriage can have a negative impact on the mental health and wellbeing of LGBTI people and their families, including those in the legal profession.
"It may also amount to discrimination on the basis of sexual orientation which is contrary to the International Covenant on Civil and Political Rights, to which Australia is a signatory."
NSW Bar Association President Arthur Moses SC said it was an extraordinary step for the medical and legal profession to speak with one voice on an issue.
"This is an important issue. The rule of law requires that all Australians are treated equally," Moses said.
"Discrimination in the Marriage Act on the basis of sexual orientation or gender identity is contrary to the rule of law.
"I'm very happy to be joining the Law Society of NSW and NSW Bar Association to campaign jointly on this issue."
Australian Olympic icon, Ian Thorpe, is the face of a national campaign in support of same-sex marriage.