Gay marriage supporters and opponents protested outside New Jersey’s statehouse yesterday as they prepared to battle the issue in the Supreme Court.

The US state allows civil unions but gay rights groups have appealed to the Supreme Court to allow full marriage equality.

Tuesday’s protest was originally organised by the anti-gay National Organisation for Marriage (NOM) but the state’s largest gay group, Garden State Equality, organised a counter protest.

The two groups kept their distance, although NOM was dwarfed by the larger pro-gay demonstration.

A gay marriage bill failed by 20 votes to 14 in January and new governor Chris Christie is on record as being against same-sex marriage.

In March, six gay couples who have had civil unions appealed to the Supreme Court to grant full equality.

The court ruled in 2006 that gay couples must be granted all the rights of marriage and left the legislature to decide how this should be enacted.

Lawmakers opted to legalise civil unions, but campaigners say they are not adequate because many employees in hospitals and insurance companies do not understand the concept.

Instead, they say, granting full marriage equality will allow gay couples to be recognised as bona fide families.

NOM president Brian Brown told the New Jersey Star-Ledger that in the 31 states where gay marriage had been put to voters, it had been rejected every time.

“How can you think that it’s right for a few judges to say [voters] don’t count?,” he said “‘Bow down to your robed masters. We’re going to make the decision.”

Speaking from a committee room inside the statehouse, Garden State Equality chairman Steve Goldstein said: “We have a different message from our opponents today. Outside is a message of hate and prejudice.”