The Netherlands Antilles has said it will appeal against a court ruling that established same-sex couples have the same rights there as they do in Holland.
The case concerned a health company that refused to accept a lesbian couple.
Like Aruba, the Netherlands Antilles is self-governing, but it remains a constituent country of the Kingdom of the Netherlands, forming a commonwealth with the State of the Netherlands.
The appeal will test the extent to which the Antilles can make their own decisions about social policy and will argue that the Dutch ideas about marriage should not take primacy.
Gay marriage is legal in the Netherlands but not on the Antilles or Aruba, but a court ruling last year forced them to recognise marriages performed in Holland.
The decision followed a row over a same-sex couple who were denied the right to register their union in Aruba.
Aruba refused to recognise same-sex marriages in 2005 although it did legalise homosexual relations between consenting adults in private.
The Netherlands Antilles was scheduled to disband on December 15, 2008, but the process has been postponed.
Two islands, Curaçao and Sint Maarten, are likely to become constituent countries of the Kingdom of the Netherlands while three others would become part of a Dutch province.