The Marriage Act 1955 is currently silent on the need for parties to a marriage to be of the opposite sex. The current refusal by registry offices to issue a licence for same sex couples rest on common law. However marriages are now allowed where one partner has changed gender.
The basis for the case is the 1993 Human Rights Amendment Bill which banned discrimination on the grounds of sexual orientation, Dr Rodney Harrison, the women lawyers said.
The women are raising $20,000 for the legal battle.