SALEM, Ore. -- Marion County Judge Vance Day is being investigated by a judicial fitness commission in part over his refusal to perform same-sex marriages on religious grounds, a spokesman for the judge said.

When a federal court ruling in May 2014 made same-sex marriage legal in Oregon, Day instructed his staff to refer same-sex couples looking to marry to other judges, spokesman Patrick Korten said Friday.

Last fall, he decided to stop performing weddings altogether, aside from one in March that had long been scheduled, Korten said.

"He made a decision nearly a year ago to stop doing weddings altogether, and the principal factor that he weighed was the pressure that one would face to perform a same-sex wedding, which he had a conflict with his religious beliefs," Korten said.

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In an email, Day declined to comment and referred questions to Korten.

The issue of same-sex weddings is "the weightiest" of several allegations against Day that are being investigated by the Commission on Judicial Fitness and Disability, Korten said.

He declined to detail any of the allegations, saying he didn't want to defy the commission, which considers complaints confidential until it is ready to make them public.

The investigation of Day's conduct comes amid heightened national attention to the responsibilities of public officials who oppose same-sex marriage. Kim Davis, a county clerk in Kentucky, went to jail Thursday because of her refusal to issue marriage licenses to same-sex couples.

Last month, the Ohio Supreme Court's Board of Professional Conduct said judges can't refuse to marry same-sex couples on personal, moral or religious grounds.

Judges who stop performing all marriages to avoid marrying same-sex couples may be interpreted as biased and could be disqualified from any case where sexual orientation is an issue, the Ohio board ruled.

The investigation of Day came to light Thursday when the Oregon Government Ethics Commission - a separate entity from the judicial fitness commission - approved the judge's request to create a legal defense fund to pay his lawyers.

Day, a former chairman of the Oregon Republican Party, was appointed to the bench in 2011 by then-Gov. John Kitzhaber, a Democrat.

Day's move concerned Jeana Frazzini, co-director of the gay-rights group Basic Rights Oregon.

"Taking that kind of a step really calls into question how an LGBTQ person could expect to be treated in a court of law," Frazzini said. "It goes beyond marriage and gets to serious questions about judicial integrity."