The US federal appeals court considering the ban on gay marriage in California could issue a narrow ruling on lifting the ban, reports say.

It is believed that the Ninth US Circuit Court of Appeals in San Francisco may issue a ruling to lift the ban in California but leave intact the bans in other states.

The three-judge panel heard two and a half hours of legal argument yesterday after gay marriage opponents launched a challenge over a federal judge’s ruling than the ban was unconstitutional.

According to the San Francisco Chronicle, lawyers for the gay couples who began the original legal action to overturn the ban argued that barring gay couples from marrying violates the US constitution.

However, the paper reported, the judges appeared keen to frame the case “more narrowly”

This may be a move designed to appeal to the Supreme Court, which is likely to hear the case in the future.

Both Judge Stephen Reinhardt, a liberal; and Judge N Randy Smith, a conservative, suggested limiting the scope of the case.

The court heard that the case could be compared to Colorado, where the Supreme Court had struck down a voter-initiative barring local governments from passing civil rights protection laws for gays and lesbians.

Charles Cooper, the lawyer for the anti-gay groups fighting to keep the California ban, argued that it should stay in place because Colorado’s measure denied gays and lesbians more rights and that the California ban sought only to preserve marriage.

He also argued that gay couples could be treated differently from straight couples because they cannot produce children.

The panel also questioned whether anti-gay groups have the legal standing to bring the case to court as California’s state officials, governor Arnold Schwarzenegger and Attorney-General Jerry Brown, have refused to defend the ban.