Citing a need for a trial record, the New Jersey Supreme Court on Monday declined to consider new arguments in a legal battle over gay marriage.

In the 2006 lawsuit Lewis v. Harris the court unanimously agreed that it is unconstitutional to deny gay and lesbian couples the rights granted to married heterosexual couples and ordered the Legislature to remedy the situation. Lawmakers responded by enacting a civil unions law.

Arguing that New Jersey's civil unions law is not equal to marriage, gay activists, led by Garden State Equality, the state's largest gay advocate, lobbied lawmakers to approve a gay marriage law.

After New Jersey senators killed such a law in January, prominent gay rights group Lambda Legal filed a motion seeking marriage equality with the high court on behalf of the plaintiffs in the original lawsuit.

In the court's split 3-3 ruling, justices said the case could not be decided on “without the development of an appropriate trial-like record” and encouraged supporters to file a new lawsuit in a lower court.

“We are terribly disappointed about today's ruling,” Hayley Gorenberg, deputy legal director at Lambda Legal, said in a statement. “This ruling now relegates our plaintiffs to second-class citizenship for even longer.”

Steve Goldstein, chair of Garden State Equality, said the court's decision served to extend the state's “caste system.”

“Because of the legislature's inability to act and the Supreme Court's decision today, New Jersey continues in a caste system where an entire people are thrown aside into a profoundly inferior status, spit on, dumped on, utterly degraded, by hospitals and employers who mock the term 'civil union.'”

Lambda Legal said it was “assessing possible next steps in Superior Court.”